Question

Find angle ABO where O is the centre of the circle

Answer 1

Answer:

1. angle OAB will become 70 (vertically opposite angle)
2. OA=OB(radius of circle)
3. therefore angle ABO will become 65 isosceles triangle property

Answer 2

Answer:

Given That :-

                     ABCD is a rectangle.

hence its diagonals will also be equal.

so AD = BC

We can see  

∠COD = ∠AOB = 70° (vertically opposite angles)

O is the intersecting point of the two diagonals and it divides them into equal  half. So,

AO = OB

so Δ AOB is isosceles

hence ∠A = ∠B

We know that sum of three angles of a Δ is equal to 180° :-

180° = ∠A+∠B+∠O

180° = 2∠B + ∠O

180° = 2∠B + ∠70°

110°  = 2∠B

∠B = 55°

Hence the value of ∠ABO is 55°.

Step-by-step explanation: