Question

what is $m\angle 1$?
(there is a triangle with angles 84° and 47°, and angle 1 is an exterior angle related to the triangle. then there is a box to fill in $m\angle 1 = \square ^\circ$ and a submit button.)

Explanation:

Step1: Identify remote interior angles

The remote interior angles to $\angle 1$ are $84^\circ$ and $47^\circ$.

Step2: Apply exterior angle theorem

The measure of an exterior angle of a triangle equals the sum of its two remote interior angles.
$m\angle 1 = 84^\circ + 47^\circ$

Step3: Calculate the sum

$m\angle 1 = 131^\circ$

Answer:

$131$