iGCSE Mathematics (0580) :C4.4 Calculate lengths of similar figures. iGCSE Style Questions Paper 1

Question

Triangle ABC is mathematically similar to triangle PQR. Calculate QR.

▶️ Answer/Explanation

Solution

Ans: 4.5 cm

Since triangles are similar, corresponding sides are proportional.

AB/PQ = AC/PR = BC/QR

8/6 = 6/QR → 4/3 = 6/QR

QR = (6 × 3)/4 = 18/4 = 4.5 cm

Question

Shape A is mathematically similar to shape B.

Calculate the value of x.

▶️ Answer/Explanation

Solution

Ans: 8 cm

Find the scale factor: 6.75 ÷ 2.7 = 2.5

Apply to the other side: x = 3.2 × 2.5

Calculate: x = 8 cm

Alternatively: 3.2/x = 2.7/6.75 → x = (3.2 × 6.75)/2.7 = 8

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