Question

what is ( mangle1 )?
( mangle1=square^{circ} )

Explanation:

Step1: Use the exterior angle theorem

The exterior angle theorem states that an exterior angle of a triangle is equal to the sum of the two non - adjacent interior angles.

Step2: Calculate \(m\angle1\)

Here, the two non - adjacent interior angles are \(46^{\circ}\) and \(39^{\circ}\). So, \(m\angle1=46^{\circ}+39^{\circ}\)

$$m\angle1 = 85^{\circ}$$

Answer:

\(85\)