Question

find ( mangle bec ).
( mangle bec=square^{circ} )

Explanation:

Step1: Identify the right angle

Since \(AB\perp AD\), \(\angle BED = 90^{\circ}\).

Step2: Use angle subtraction

We know that \(\angle BEC+\angle CED=\angle BED\). Given \(\angle CED = 48^{\circ}\), then \(m\angle BEC=\angle BED-\angle CED\).
Substitute the values: \(m\angle BEC = 90^{\circ}- 48^{\circ}\).

Answer:

\(42\)