Question

ABC is a right triangle with right angle C. Ab = 18 cm m What is BC

Round answer to nearest tenth

Answer 1

check the picture below.

make sure your calculator is in Degree mode.

Answer 2

Make notes of these
sin = opposite/hypotenuse
cos = adjacent/hypotenuse
tan = opposite/adjacent

in your problem you have opposite of 22 degrees and adjacent - so you can only use tan

tan 22 = x/18
solve for x (which is your BC)