Question

If the measures of the angles of a triangle are in the ratio 1:3:5 , the number of degrees in the measure of the smallest angle is

a. 10
b. 20
c. 60
d. 180

Answer 1

9a = 180
Divide both sides by 9
a = 20
.
Substituting back into the formulas we defined.
a = 20
b = 3a = 3(20) = 60
c = 5a = 5(20) = 100
.
Check the work.
Does 20 + 60 + 100 = 180?
Yes.

Answer 2

where did the 9 come from @kumar2006