D. 5.9
math question don't guess

Choice D) 5.9

We'll be using the tangent rule two times to find the lengths of BD and BC, which we'll subtract to compute the length of CD. Make sure your calculator is in degree mode.

Focus on triangle ABC for now (ignore point D)

For reference angle A:

AB = adjacent = 85

BC = opposite = unknown = x

tan(angle) = opposite/adjacent

tan(A) = BC/AB

tan(28) = x/85

x = 85*tan(28)

x = 45.1953

Now focus on triangle ABD (ignore point C)

For reference angle A:

AB = adjacent = 85

BD = opposite = unknown = y

tan(angle) = opposite/adjacent

tan(A) = BD/AB

tan(31) = y/85

y = 85*tan(31)

y = 51.0732

Subtract x and y (large-small)

y-x = 51.0731-45.1953 = 5.8778

this rounds to 5.9

if a = 1,   and b = 2, then the answer is 47.99999999. if you round that to the nearest whole number, the answer is 48.

360/29

step-by-step explanation: