Answer:
The measure of angle R is 20°.
Step-by-step explanation:
Since, We know that,
When two triangles are similar then their corresponding angles are congruent or the measures of corresponding angles are equal,
In triangles MNO and PQR,
Angles M, N and O are corresponding to angles P, Q and R.
Given,



Also, By the above property,


Now, the sum of all interior angles of a triangle is supplementary,
So, in ΔPQR,




Hence, the measure of angle R is 20°.