17) let the unknown be x.
tanx = 3.5
x = tan⁻¹(3.5) use your calculator
x ≈ 74.05° x ≈ 74.1 to the nearest tenth
18)
tan 34 = x/20
20*tan34 = x
20*(0.6745) ≈ x
13.49 ≈x
x ≈ 13.49 x ≈ 13.5 to the nearest tenth
19) tan2° = 2/x
x = 2/tan2°
x = 2/0.0349
x ≈57.31 x ≈ 57.31 to the nearest tenth
20) tanx = 90
x = tan⁻¹(90) Use your calculator
x ≈ 89.36°
x ≈ 89.4° to the nearest tenth.