Final answer:
In quadrant III, if cos(θ) = -7/8, the value of tan(θ) is -15/7.
Step-by-step explanation:
To find the value of tan(θ) when cos(θ) = -7/8 in quadrant III, we can use the trigonometric identity tan(θ) = sin(θ)/cos(θ).
In quadrant III, cos(θ) is negative and sin(θ) is also negative.
Since we have cos(θ) = -7/8, we can write sin(θ) = √(1 - cos^2(θ)) to find the value of sin(θ).
Using these values, we can calculate tan(θ) = sin(θ)/cos(θ).
Therefore, the value of tan(θ) is 15/7 or -15/7.