Answer
18$^\circ$, 72$^\circ$, and 90$^\circ$
Work Step by Step
The sum of the measures of the angles of a triangle is always 180$^\circ$.
x+4x+5x=180
5x+5x=180
10x=180
x=$\frac{180}{10}$
x=18$^\circ$
4x=4(18)=72$^\circ$
5x=5(18)=90$^\circ$