Question

isosceles triangles
triangle abc is an isosceles right triangle. what is the measure of one base angle?
90°
30°
45°
60°

Explanation:

Step1: Recall triangle angle sum property

The sum of angles in a triangle is \(180^{\circ}\). In an isosceles right - triangle, one angle is \(90^{\circ}\). Let the base angles be \(x\) (since the triangle is isosceles, the base angles are equal).

Step2: Set up the equation

Using the angle - sum property of a triangle: \(90 + x+x=180\). Simplify the equation to \(90 + 2x=180\).

Step3: Solve for \(x\)

Subtract \(90\) from both sides: \(2x=180 - 90\), so \(2x = 90\). Then divide both sides by \(2\): \(x=\frac{90}{2}=45\).

Answer:

\(45^{\circ}\)