Question

8. Lines AB and CD intersect each other at
O.If angle AOC : angle BOC = 2:7 then
angle BOD equals *
(2 Points)
20°
40°
60°
80°​

Answer 1

AB and CD interest each other at O .

and angle AOC :. BOC = 2:7

let angle AOC is 2x and BOC is 7x

we know sum of straight line angle is 180°.

so, AOC+ BOC = 180°

2x + 7x = 180°

9x = 180°

x = 20°

now angle AOC = 40° and BOC = 140°

then , angle BOD = AOC [because of vertically opposite angle]

so, angle BOD is 40° .