GCSE Maths Practice: perimeter-and-area

Question 5 of 10

This question calculates the perimeter of a semicircle given its diameter.

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\( \begin{array}{l}\text{Find the perimeter of a semicircle with diameter } 8\,\text{cm}, \text{ giving your answer in terms of } \pi.\end{array} \)

Choose one option:

Compute half circumference (πr) then add diameter. Keep π in the answer.

The perimeter of a semicircle includes the curved part (half the circumference) and the straight diameter. Formula: P = πr + diameter. For diameter 8 cm, radius r = 4 cm, so curved part = π × 4 = 4π, add diameter = 8, total perimeter = 4π + 8. Recognizing which part is curved and which is straight is essential. This method is used in designing arches, semi-circular paths, or gates. Practice with different diameters to reinforce understanding.