Question

The bottom side of the quadrilateral 5cm is a diameter of the circle and the top side 3 cm is a chord parallel to it Calculate the area of the quadrilateral

Answer 1

Answer:

Given,

AB is equal to the radius of the circle.

In △OAB,

OA=OB=AB= radius of the circle.

Thus, △OAB is an equilateral triangle.

∠AOC=60°

Also, ∠ACB=

2

1

∠AOB=

2

1

×60°=30°

ACBD is a cyclic quadrilateral,

∠ACB+∠ADB=180° ∣ Opposite angles of cyclic quadrilateral

⇒∠ADB=180°−30°=150°

Thus, angle subtend by the chord at a point on the minor arc and also at a point on the major arc are 150° and 30° respectively.