How to do this sum

Dear Student

Ans 9.
In a right isosceles triangle, one angle is a right angle and the the other two angles are equal.
Let the equal angles measure x.
Now, x + x + 90° = 180° (Angle sum property)
2x = 180° - 90°
2x = 90°
x = 45°
Thus, the equal angles of the right isosceles triangle measure 45^o​.

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