Question

In ΔABC, if the length of sides a, b, and c are 3.5 centimeters, 5.5 centimeters, and 6 centimeters respectively, what is m∠C to two decimal places?

Answer 1

We are given with three sides with measurements such as below:
a = 3.5 cm 
b = 5.5 cm
c = 6 cm
We are asked to solve for m∠C. To solve this we need to apply Law of Cosines such as below:
cos C = a²+b² - c² /2ab
cos C = 3.5² + 5.5² -6² / (2*3.5*5.5)
cos C = 0.16883
C = 80.28°

The answer is 80.28°.

Answer 2

Answer:

m∠C=80.21 degrees

Step-by-step explanation:

We are given with three sides with measurements such as below:

a = 3.5 cm  

b = 5.5 cm

c = 6 cm

Then we can use cosine theorem as below:

$c^2=a^2+b^2-2ab*cos(C)\\36=12.25+30.25-2*3.5*5.5*cos(C)\\2*3.5*5.5*cos(C)=6.5\\cos(C)=0.17\\C=80.21$