Isoceles Angle Bisector

Geometry Level 1

Triangle $ABC$ is isosceles with $AB = AC$ . $D$ is a point on $BC$ such that $AD$ bisects $\angle BAC$ . What is the measure of $\angle ADB$ (in degrees)?

The answer is 90.

1 solution

Arron Kau Staff
May 13, 2014

In an isosceles triangle, the angle bisector of the vertex angle would be the perpendicular bisector of the opposite side. This follows by symmetry. Thus $\angle ADB = 90^\circ$ .

Isoceles Angle Bisector

The answer is 90.

1 solution

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