Question

or
Find AB.
3
A
B
C
42°
Write your answer as an integer or as a decimal rounded to the nearest tenth.
AB =

Answer 1

I can’t be sure what the diagram means from the text alone. Could you either upload a picture or clarify which side is length 3 and where the 42° angle is (and whether the triangle is right-angled and where the right angle is)?

Meanwhile, here are the common interpretations and how to get AB in each case (using SOH CAH TOA). I’ll give the numeric answers rounded to the nearest tenth.

1) If the side of length 3 is the leg adjacent to the 42° angle and AB is the hypotenuse:
AB = (adjacent) / cos(42°) = 3 / cos(42°) ≈ 3 / 0.7431448 ≈ 4.0

2) If the side of length 3 is the leg opposite the 42° angle and AB is the hypotenuse:
AB = (opposite) / sin(42°) = 3 / sin(42°) ≈ 3 / 0.6691306 ≈ 4.5

3) If the side of length 3 is the adjacent leg and AB is the other (opposite) leg:
AB = (adjacent) * tan(42°) = 3 * tan(42°) ≈ 3 * 0.900404 = 2.7

Tell me which of these matches your diagram (or send the image) and I’ll give the final answer.