Given: \(∠\)POY= 90° and a: b = 2: 3.
Let the common ratio between a and b be x.
∴ XY is a straight line, rays OM and OP stand on it.
∴\(∠\)POY = \(∠\)POX = 90°
\(∠\)POX = ∠POM + \(∠\)MOX
90° = a + b
Now, a = 2x and b = 3x
\(⇒ \)a + b = 90°
2x + 3x = 90°
5x = 90°
x = \(\frac{90°}{5}\) = 18°
a = 2x = 2 \(×\) 18°
a = 36°
b = 3x = 3 × 18°
b = 54°
Also, \(∠\)MOY= \(∠\)MOP + \(∠\)POY
= a + 90°
= 36° + 90° = 126°
∴ c = 126º