Find the value of x and measure the exterior angle of the given Triangle.

Solution:

We have the exterior angle of a triangle equal to the sum of two interior opposite angles.

Here, (3x - 10°) is exterior angle 

25° and x + 15° are interior opposite angles.

∴ 3x -10° = 25° + x +15°

2x = 50°

x = 25°

The exterior angle = 3x-10 

3(25) - 10 = 75 -10 = 65°

Find the value of x and measure the exterior angle of the given Triangle.

Summary:

The value of x of the given triangle is x = 25 and the measure of the exterior angle is 65°