In ΔDEF, d = 5.3 cm, e = 2.4 cm and f=4.7 cm. Find the measure of ∠F to the nearest 10th of a degree.

Given:

In ΔDEF, d = 5.3 cm, e = 2.4 cm and f=4.7 cm.

To find:

The measure of ∠F to the nearest 10th of a degree.

Solution:

According to the law of cosine:

In ΔDEF,

Putting the given values d = 5.3, e = 2.4 and f=4.7, we get

Taking cos inverse on both sides, we get

Therefore, the measure of angle F is 62.5 degrees.