Answer:
Option C. 6.5
Explanation:
From the question given above, the following data were obtained:
Angle B = 80°
Side opposite B (b) = 10
Angle C = 40°
Side opposite C (c) =?
We can obtain the value of c by using the sine rule as illustrated below:
b / Sine B = c / Sine C
10 / Sine 80 = c / Sine 40
Cross multiply
c × Sine 80 = 10 × Sine 40
Divide both side by Sine 80
c = (10 × Sine 40) / Sine 80
c = 6.5
Thus, the value of c is 6.5