Question

In ΔJKL, j = 74 cm, k = 14 cm and l=80 cm. Find the measure of ∠J to the nearest degree.

Answer 1

Answer:

  ∠J = 60°

Step-by-step explanation:

The Law of Cosines tells you ...

  j² = k² +l² -2kl·cos(J)

Solving for J gives ...

  J = arccos((k² +l² -j²)/(2kl))

  J = arccos((14² +80² -74²)/(2·14·80)) = arccos(1120/2240) = arccos(1/2)

  J = 60°

_____

Additional comment

It is pretty rare to find a set of integer side lengths that result in one of the angles of the triangle being a rational number of degrees.