Question

find the value of x
a. 65 degrees
b. 85
c. 70
d. 180 degrees
e. 90 degrees
f. 72 degrees
g. 180
h. 72

Explanation:

Step1: Recall angle - sum property of isosceles triangle

In an isosceles triangle, the base - angles are equal. Let the base - angles be \(y\). The sum of interior angles of a triangle is \(180^{\circ}\).

Step2: Set up the equation

We know one base - angle \(y = 55^{\circ}\) (assuming the given \(55^{\circ}\) is a base - angle), and the sum of interior angles of a triangle \(A + B + C=180^{\circ}\). So \(x + 55^{\circ}+55^{\circ}=180^{\circ}\).

Step3: Solve for \(x\)

\[

$$\begin{align*} x&=180^{\circ}-(55^{\circ}+ 55^{\circ})\\ x&=180^{\circ}-110^{\circ}\\ x& = 70^{\circ} \end{align*}$$

\]

Answer:

C. 70