Question

Find DE, the question is in the picture below

Answer 1

The value of DE is 6.8

To determine the value of the length, we have that;

Using the cosine identity, we have;

cos 65 = x/11

cross multiply the values, we get;

x = 11cos 65

x = 11 × 0. 422

x = 4. 6

Now, to determine the value of the side DE, we have;

Using the Pythagorean theorem, we get;

DE²= 5² + 4.6²

DE² = 25 + 21. 4

add the values

DE² = 46. 4

Find the square root

DE = 6.8