Question 45
Mensuration of Plane ShapesPQR is the diameter of a semicircle RSP with centre at Q and radius of length 3.5cm. If QPT = QRT = 60°, find the perimeter of the figure PTRS (π = 22/7)
- A.25cm
- B.18cm
- C.36cm
- D.29cm
- E.25.5cm.
Show the answer and explanation
Answer: A (25cm)
Explanation
Triangle PTR has two 60° angles, so it is equilateral with side PR = 7cm. The semicircular arc is ½ × 22/7 × 7 = 11cm. Perimeter = 11 + 7 + 7 = 25cm.