If m is 21 inches, k is 34 inches, and ∠J measures 60°, then find j using the Law of Cosines. Round your answer to the nearest tenth.

Answer:
j = 29.7 inches
Step-by-step explanation:
The following data were obtained from the question:
m = 21 inches
k = 34 inches
Angle L = 60°
j =?
Using Cosine rule, the value of j can be obtained as follow:
j² = m² + k² – 2mk Cos J
j² = 21² + 34² – 2 × 21 × 34 × Cos 60°
j² = 441 + 1156 – 1428 × 0.5
j² = 1597 – 714
j² = 883
Take the square root of both side
j = √883
j = 29.7 inches
Therefore, the value of j is 29.7 inches.