Answer: see below
Step-by-step explanation:
Presuming you meant this
0< θ < 90 degree; tan (θ) = 7/8 find cos (θ)
Using the identity
1 + tan²θ = sec²θ (where sec θ = 1/cosθ)
cosθ = √{1/(1 + tan²θ)} = √{ 1/(1 + (7/8)²} = √{ 1/(1 + 49/64)}
= √{ 64/113} = 8/√113 <= answer.
