Question

in the given figure ABCD is a rectangle whose diagonals AC and BD intersect each other at O if angle OAB= 20 degree find angle abc

Answer 1

angle obc =90-28=62
as the sum of the angles are complementary.

Answer 2

<BAD = 90° ( ABCD is a rectangle)

<CAD = <BAD-28
= 90 - 28
= 62°
<CAD = 62°

Now,
In Triangle CAD and DBC
<ADC = <BCD (each 90°)
AD = BC (Opposite sides of rectangle)
CD =DC (common)

So, Triangle CAD congurent Triangle DBC
(By S. A. S criteria)

<DBC = <CAD (C. P. C. T)
< DBC = 62°

<OBC = 62°