Question

On a piece of paper, use a protractor to construct right triangle DEF with DE=4 in. , m∠D=90° , and m∠E=45° .

Answer 1

Let's see .. . .

D


E F

Since one of the angle is 90 degree, it would be very likely that the other side could be paired with the principle of Pythagoras.
The Pythagoras match for 4 is 3 and 5, so

DE = 4 in
EF = 3 in
Df = 5 in