Question

Find the following ratio DEF\triangle D E F where mEm \angle E = 9090^\circ DE = 4, EF= 3, DF = 5.

cosD\cos D

Solution

Verified
Step 1
1 of 2

Recall that:

cosθ=length of the side adjacent to the angle θlength of the hypotenuse\cos\theta=\dfrac{\text{length of the side {\color{#c34632}\bf{}adjacent} to the angle $\theta$}}{\text{length of the {\color{#c34632}\bf{}hypotenuse}}}

Use the given figure to substitute the lengths of

adjacentside{\color{#c34632}\bf{}adjacent side}

and

hypotenuse{\color{#c34632}\bf{}hypotenuse}

.

cosD=DEDF=45\cos D=\dfrac{DE}{DF}=\dfrac{4}{5}

Create an account to view solutions

Create an account to view solutions

More related questions

1/4

1/7