Question

find the value of y.

1. a 65° c b f d e y°

Explanation:

Step1: Calculate angle in first triangle

In triangle \(ABC\), using the angle - sum property of a triangle (\(A + B + C=180^{\circ}\)). Given \(A = 65^{\circ}\), \(C = 90^{\circ}\). Let \(B=x\), then \(x+65^{\circ}+90^{\circ}=180^{\circ}\). So \(x = 180^{\circ}-(65^{\circ}+90^{\circ})=25^{\circ}\).

Step2: Use congruent angles

Assume \(\triangle ABC\cong\triangle DEF\) (by AAS or ASA, as right - angles are equal and other angles can be congruent). Then \(y = 25^{\circ}\) (corresponding angles of congruent triangles are equal).

Answer:

\(25\)