Exercise 2 Page 674

For any △ ABC, let the lengths of the sides opposite angles A, B, and C be a, b, and c, respectively.

sin A/a=sin B/b=sin C/c Let's use this law to find the value of x. Consider the given triangle.

We know that the length of a side is 18 and that the measure of its opposite angle is 20. We want to find the length of the side that is opposite to the angle whose measure is 135. We can use the Law of Sines again! sin 20/18=sin 135/x Let's solve the above equation for x using the Cross Product Property.

sin 20/18=sin 135/x

▼

Solve for x

CrossMult

Cross multiply

sin 20* x=sin 135* 18

DivEqn

.LHS /sin 20.=.RHS /sin 20.

x=sin 135* 18/sin 20

UseCalc

Use a calculator

x=37.213954...

RoundDec

Round to 1 decimal place(s)

x≈ 37.2