Question

In ΔABC, If a = 26 cm, b = 30 cm, cos C = $\frac{63}{65}$, then find c.

Answer 1

Answer:

The required value is  " c = 8 ".

Given that

In ΔABC, If a = 26 cm, b = 30 cm, cos C = 63/65

We know that

$cosC=\frac{a^{2}+b^{2}-c^{2} }{2ab}\\ \\cosC=\frac{26^{2}+30^{2}-c^{2}}{2(26)(30)}\\\\\frac{63}{65} =\frac{1576-c^{2}}{1560}\\\\\frac{63}{65}(1560) =1576-c^{2}\\\\1512=1576-c^{2}\\\\c^{2}=1576-1512\\\\c^{2}=64\\\\c=8$

Answer 2

Answer:

c^2=64

c=8

:.a= 26

:.b=30

:.c=8