Question

which equation can be solved to find one of the missing side lengths in the triangle? cos(60°) = 12/a cos(60°) = 12/b cos(60°) = b/a

Explanation:

Step1: Identify triangle type and given info

Right triangle at C, angle B=60°, hypotenuse AB=12, legs a(BC), b(AC).

Step2: Apply cosine to angle B

cos(60°)=adjacent/hypotenuse= a/12 (adjacent=BC=a, hypotenuse=AB=12).

Step3: Evaluate options

Options 1 (12/a) and 2 (12/b) give legs >12 (invalid). Option 3 (b/a) is valid ratio (cos(60°)=0.5=b/a).

Answer:

cos(60°) = b/a