Question

In the adjacent figure,ABCD is a square such that ABO is an equilateral triangle. Find:-
(a) angle BCO
(B) Reflex angle AOC​

Answer 1

Step-by-step explanation:

angle OBC = 90° - angle ABO [ AOB is an equilateral triangle ]

=> |OBC = 90°- 60° => 30°................1

now ∆ OBC is an isosceles ∆ as OB = BC

(a) |OBC + |BOC + |OCB = 180°

=> 30° + 2|BCO = 180° [ BO = BC, angles opposite to equal sides are equal ]

=> 2|BCO = 180° - 30° = 150°

=> |BCO = 150°/2 => 75° Answer for part (a)

(b) |AOC = |AOB + |BOC

=> |AOC = 60° + 75° => 135° answer part (b)

[ |BOC = |BCO = 75° and as ∆ AOB is equilateral ∆ |AOB = 60° ]