Answer:

Step-by-step explanation:
we know that
In the triangle abc
if 
then

Because, the sum of the interior angles in a triangle must be equal to 180 degrees
therefore
Triangle abc is a right triangle
see the attached figure to better understand the problem
The sine of angle a is equal to divide the opposite side to angle a by the hypotenuse
so

The cosine of angle b is equal to divide the adjacent side to angle b by the hypotenuse
so

therefore

When two angles are complementary, the sine of one angle is equal to the cosine of the other angle and the cosine of one angle is equal to the sine of the other angle
so


7 3/10 + 6 1/3 + 2 7/10
First change them to improper fractions
73/10 + 19/3 + 27/10
now find the common denominator which would be 30
73/10 = 219 /30
19/3 = 190/30
27/10 = 81 /30
now add (219 + 190 + 81) = 490/30
now divide 490 ÷ 30 = 16 1/3
Your answer is 16 1/3
Hope this helps. :)
C is the correct answer.<span />