Find the value of angle \(b\) for the following right angled triangle \(PQR\) if the angle \(a =\) 72\(°\).
  
ex4_1.png
  
Answer:
 
For a right angled triangle, one of the angles is \(^{\circ}\).
 
The property used to determine the value of angle \(b\) is
 
The measure of angle \(b\) is \(°\)