Question

Find the value of [x]. There is no need to put degrees or the symbol. It is assumed that it is in degrees.

Answer 1

90°

Step-by-step explanation:

The sum of interior angles in a triangle is equal to 180°.

Since this is an isosceles triangle, the angle measures for the base angles will be congruent, so the measure of x:

45° + 45° + x = 180°

• Add like terms.

90° + x = 180°

• Subtract 90° from both sides.

x = 90°

Answer 2

The value of x is
`90\textdegree`.

As shown in the figure, the triangle has two sides equal. Hence it is an isosceles triangle. The isosceles triangle theorem states that if two sides of a triangle are congruent, then the angles opposite those sides are also congruent. So, the third angle is also 45 degrees.

The value of x can be found using the fact that the sum of angles in a triangle is
`180\textdegree`. So,

45+45+x=180

90+x=180

x=180-90

x=90

The value of x is
`90\textdegree`