Answer:
38°
Step-by-step explanation:
The measure of required angle can be obtained by using cosine law.
From the given triangle we find that:
a = 5, b = 3, c = 7,
Since,
cos (A) = (b^2 +c^2 - a^2) /2bc
Therefore,
cos (A) = (3^2 + 7^2 - 5^2) /(2*3*7)
cos (A) = (9 + 49 - 25) /(42)
cos (A) = (33) /(42)
cos (A) = 0.785714286
A = arccos(0.785714286)
A = 38.213210675°
A = 38°
The formula you need to use is C = 5/9•(F - 32)
So take 15 and subtract 32: 15-32 = -17
Then multiply that by 5/9: 5/9•(-17) ≈ -9.44
