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Mathematics questions, chapter 10

Gradient of a Straight Line

43 marks. Use Practice to check each answer as you go, or Exam to answer everything first. Show your working for Section B.

Section A: objective questions

12 marks
Choose the correct answer. Each question carries 1 mark.
1

Question 1

The gradient of a straight line is the ratio of
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B
Gradient = vertical distance ÷ horizontal distance (rise over run). Option A is upside down, so a steeper line would give a smaller number.
For the teacher: Remembering, low difficulty, standard 10.1.1
Textbook p. 192
2

Question 2

Line KL makes an angle of 45° with the x-axis and line MN makes an angle of 30° with the x-axis. Both lines rise to the right. Which statement is true?
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A
The larger the angle from the x-axis, the steeper the line and the greater the gradient. 45° is larger than 30°, so KL is steeper.
For the teacher: Understanding, low difficulty, standard 10.1.1
Textbook p. 191
3

Question 3

Diagram 1 shows a ramp AB. What is the gradient of AB?
Right-angled triangle for ramp AB: horizontal distance 12 m, vertical distance 5 m
Diagram 1
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C
Gradient = vertical ÷ horizontal = 5 ÷ 12. Option A is horizontal ÷ vertical. 17 comes from adding 5 + 12.
For the teacher: Applying, low difficulty, standard 10.1.1
Textbook p. 192
4

Question 4

What is the gradient of the straight line passing through A (2, 3) and B (6, 11)?
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D
m = (11 − 3) ÷ (6 − 2) = 8 ÷ 4 = 2. Option A is the inverse (4 ÷ 8).
For the teacher: Applying, low difficulty, standard 10.1.2
Textbook p. 194
5

Question 5

Find the gradient of the straight line passing through P (2, 3) and Q (8, 5).
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A
m = (5 − 3) ÷ (8 − 2) = 2 ÷ 6 = 1/3. Option B divides change in x by change in y. Option C adds the coordinates instead of subtracting.
For the teacher: Applying, low difficulty, standard 10.1.2
Textbook p. 194
6

Question 6

A straight line has x-intercept −6 and y-intercept 9. Its gradient is
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C
m = −(y-intercept) ÷ (x-intercept) = −9 ÷ (−6) = 3/2. The two minus signs make a positive gradient. Option A forgets the minus sign in the formula.
For the teacher: Applying, low difficulty, standard 10.1.2
Textbook p. 194
7

Question 7

Which straight line has an undefined gradient?
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B
Both points have x = 2, so the line is parallel to the y-axis and x₂ − x₁ = 0, which cannot be a divisor. Option A is parallel to the x-axis, so its gradient is 0.
For the teacher: Understanding, low difficulty, standard 10.1.3
Textbook p. 196
8

Question 8

Diagram 2 shows four straight lines P, Q, R and S drawn from the origin. Which line is the steepest?
Four lines from the origin: P to (4, 2), Q to (1, 3), R to (−1, 4), S to (−4, 2)
Diagram 2
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D
Steepness depends on the absolute value of the gradient. P has m = 1/2, Q has m = 3, R has m = −4 and S has m = −1/2. The greatest absolute value is |−4| = 4, so R is the steepest. Q has the greatest gradient value, but its line is less steep than R.
For the teacher: Analysing, medium difficulty, standard 10.1.3
Textbook p. 196
9

Question 9

Each step of a staircase is 18 cm high and 24 cm deep. The gradient of the staircase is
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B
Vertical ÷ horizontal = 18 ÷ 24 = 3/4. Option A is upside down. Option D adds the two distances.
For the teacher: Applying, low difficulty, standard 10.1.4
Textbook p. 197
10

Question 10

A straight line passes through the point (0, −6) and has a gradient of 3. Its x-intercept is
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A
x-intercept = −(y-intercept) ÷ m = −(−6) ÷ 3 = 2. Option B forgets the minus sign in the formula.
For the teacher: Applying, low difficulty, standard 10.1.5
Textbook p. 198
11

Question 11

A straight line passes through the point (6, 0) and has a gradient of −32. Its y-intercept is
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D
y-intercept = −m × (x-intercept) = −(−3/2) × 6 = 9. Option A drops the minus sign in the formula. Options B and C use 6 ÷ (3/2) = 4, which is the wrong rearrangement.
For the teacher: Applying, low difficulty, standard 10.1.5
Textbook p. 199
12

Question 12

The gradient of the straight line passing through P (2, k) and Q (6, 10) is 32. Find the value of k.
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C
(10 − k) ÷ (6 − 2) = 3/2, so 10 − k = 6 and k = 4. Option B adds 6 instead of subtracting.
For the teacher: Analysing, medium difficulty, standard 10.1.5
Textbook p. 203

Section B: structured questions

31 marks
Answer all questions. Show your working.
13

Question 13

Diagram 3 shows two playground slides, P and Q.
Slide P is a right triangle with height 2.4 m and horizontal distance 3.0 m. Slide Q has height 3.0 m and horizontal distance 2.5 m
Diagram 3
[1 mark] (a)Calculate the gradient of slide P.
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Tick each point you got.
[1 mark] (b)Calculate the gradient of slide Q.
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[1 mark] (c)Which slide is steeper? Give a reason.
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For the teacher: Understanding, low difficulty, standard 10.1.1
Textbook p. 192
14

Question 14

Diagram 4 shows a straight line AB. It cuts the x-axis at A and the y-axis at B.
Line AB through A on the x-axis at 8 and B on the y-axis at −6
Diagram 4
[2 marks] (a)State the x-intercept and the y-intercept of AB.
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Tick each point you got.
[2 marks] (b)Calculate the gradient of AB.
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[1 mark] (c)State whether the gradient is positive or negative, and how you can tell from Diagram 4.
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For the teacher: Applying, low difficulty, standard 10.1.2
Textbook p. 194
15

Question 15

Four straight lines are given by two points each: AB through A (1, 2) and B (5, 2), CD through C (3, −1) and D (3, 6), EF through E (0, 0) and F (2, 6), and GH through G (1, 5) and H (4, −1).
[2 marks] (a)Find the gradient of AB and of CD.
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[2 marks] (b)Find the gradient of EF and of GH.
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[1 mark] (c)Arrange the gradients of AB, EF and GH in descending order.
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For the teacher: Analysing, low difficulty, standard 10.1.3
Textbook p. 196
16

Question 16

A straight line passes through P (0, 6) and has a gradient of −32.
[2 marks] (a)Find the x-intercept of the line.
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[2 marks] (b)The line also passes through Q (8, k). Find the value of k.
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Check with the intercepts: the line crosses the x-axis at (4, 0), and going 4 more along x drops y by 6, so y = −6.
Tick each point you got.
For the teacher: Applying, medium difficulty, standard 10.1.5
Textbook p. 198
17

Question 17

The vertices of a quadrilateral ABCD are A (−2, 1), B (1, 4), C (5, 2) and D (2, −1).
[2 marks] (a)Calculate the gradients of AB, BC, CD and DA.
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[2 marks] (b)Name the type of quadrilateral and give a reason.
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For the teacher: Analysing, medium difficulty, standard 10.1.5
Textbook p. 199
18

Question 18

Amir wants the gradient of the line through P (2, 5) and Q (6, −3). His working is: m = (6 − 2) ÷ (−3 − 5) = 4 ÷ (−8) = −1/2.
[1 mark] (a)Is Amir's answer correct? State his mistake.
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Tick each point you got.
[2 marks] (b)Show the correct working and answer.
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For the teacher: Evaluating, high difficulty, standard 10.1.2
Textbook p. 194
19

Question 19

A is the point (2, 3). Write the coordinates of a point B, different from A, so that the line AB has
[1 mark] (a)a gradient of 2.
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(3, 5): m = (5 − 3) ÷ (3 − 2) = 2
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[1 mark] (b)a gradient of zero.
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(7, 3): the line is parallel to the x-axis
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[1 mark] (c)an undefined gradient.
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(2, 8): the line is parallel to the y-axis
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For the teacher: Creating, high difficulty, standard 10.1.3
Textbook p. 196
20

Question 20

Diagram 5 shows the roof of a house. The roof is an isosceles triangle with a width of 24 m and a height of 5 m.
Isosceles triangle roof with a base of 24 m and a vertical height of 5 m drawn to the middle of the base
Diagram 5
[2 marks] (a)Calculate the gradient of the roof.
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[2 marks] (b)Calculate the length of one slanting side of the roof.
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Pythagoras' theorem: slant² = vertical² + horizontal². 5, 12 and 13 form a Pythagorean triple.
Tick each point you got.
For the teacher: Applying, medium difficulty, standard 10.1.5
Textbook p. 203