Algebra 4

4 marks · Normal

A rectangle has base cm and height cm. Its area is given by .

(a)

Calculate the area when and .

[1 mark]

(b)

Find when and .

[2 marks]

(c)

Make the subject of the formula for area.

[1 mark]

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(a) 40 cm^2

(b) 9 cm

Common mistakes: Incorrect rearrangement for b; Calculation errors

Show mark scheme and worked solution

Marking points

A1 (a) · 1 mark · Correct calculation of area: 8 × 5 = 40.

M1 (b) · 1 mark · Rearranges to h = A/b or shows working.

A2 (b) · 1 mark · Correct evaluation: h = 36/4 = 9.

B1 (c) · 1 mark · States correct rearranged formula b = A/h.

Worked solution

a) Area = 8 × 5 = 40 cm². b) h = A/b = 36/4 = 9 cm. c) b = A/h