Question

find the angle which is equal to its complement

Answer 1

let the angle be x 
its compliment be 90- x then 
According to question 90 - x = x 
                                   90      = 2x 
                                   45°    = x 
                                   45°    = 90-x...

Answer 2

Let the equal angles be x ,
x + x = 90°
=> 2x = 90°
=> x = 90°/2
=> x = 45°

the angle which is equal to its complement is equal to 45°