Question

In triangle DEF, EF = 4cm, DF = 7cm, Find angle D
And E is the right angle

Answer 1

Hello !

1. The triangle

D

I\
I \
I \
I \ 7cm
I \
I \
I \

E 4cm F

2. Find the ratio of the angle D

The ratio = hypotenuse ; opposite

⇒ calculate sin(D)

3. Calculate the angle D

sin(D) = opposite/hypotenuse = 4/7

arcsin(4/7) ≈ 34,84.. ≈ 35°

4. Conclusion

The angle D measures 35°.