Question

If A=40°, B= 60° and a=12 cm find b.

Answer 1

I will draw the triangle to show the given information

To find b we will use the sine rule

`(a)/(\sin A)=(b)/(\sin B)`

Since a = 12

Since < A = 40 degrees

Since

Substitute them in the rule above

`(12)/(\sin40)=(b)/(\sin 60)`

By using the cross multiplication

`\begin{gathered} b*\sin 40=12*\sin 60 \\ b\sin 40=12\sin 60 \end{gathered}`

Divide both sides by sin 40

`\begin{gathered} (b\sin40)/(\sin40)=(12\sin 60)/(\sin 40) \\ b=16.16755626 \end{gathered}`

The value of b is about 16.17 cm to the nearest 2 decimal places