Question

Isosceles triangle PQR in which PQ = PR = 45 mm and PQR = 20° Picture​

Answer 1

An isosceles triangle have two equal sides and two equal angles.

The measure of angles in $\triangle PQR$ are: 20, 20 and 140 degrees

Given that:

$PQ = PR = 45mm$

$\angle PQR = 20^o$

I've added as an attachment, triangle $\triangle PQR$

From the attached triangle, we have:

$\angle PQR = \angle QRP = 20^o$ --- base angles of isosceles triangle

So, we have:

$\angle PQR + \angle QRP +\angle RPQ = 180^o$ --- angles in a triangle

This gives:

$20^o + 20^o +\angle RPQ = 180^o$

$40^o +\angle RPQ = 180^o$

Collect like terms

$\angle RPQ = 180^o - 40^o$

$\angle RPQ = 140^o$

Hence, the angles of $\triangle PQR$ are:

$\angle RPQ = 140^o$

$\angle PQR = 20^o$

$\angle QRP = 20^o$

Read more about isosceles triangles at:

brainly.com/question/6238271-