Past Papers’ Solutions | Cambridge International Examinations (CIE) | AS & A level | Mathematics 9709 | Pure Mathematics 1 (P1-9709/01) | Year 2019 | May-Jun | (P1-9709/12) | Q#5
The diagram shows a semicircle with diameter AB, centre O and radius r. The point C lies on the circumference and angle AOC = radians. The perimeter of sector BOC is twice the perimeter of sector AOC. Find the value of correct to 2 significant figures.
We are required to find the value of angle AOC = radians.
We are given that the perimeter of sector BOC is twice the perimeter of sector AOC.
Expression for perimeter of a sector with radius and angle rad is;
Since AB is diameter of the semi-circle;
Now we can write;