Since it is a right triangle, you can use the trigonometric ratio sin(θ) to solve the exercise:
[tex]\sin (\theta)=\frac{\text{opposite side}}{\text{hypotenuse}}[/tex]
Graphically,
So, in this case, you have
[tex]\begin{gathered} \theta=54\text{\degree} \\ \text{ Opposite side }=72 \\ \text{ Hypotenuse }=x \\ \sin (54\text{\degree})=\frac{72}{x} \\ \text{ Multiply by x from both sides of the equation} \\ \sin (54\text{\degree})\cdot x=\frac{72}{x}\cdot x \\ \sin (54\text{\degree})\cdot x=72 \\ \text{ Divide by }\sin (54\text{\degree})\text{ from both sides of the equation} \\ \frac{\sin(54\text{\degree})\cdot x}{\sin(54\text{\degree})}=\frac{72}{\sin(54\text{\degree})} \\ x=\frac{72}{\sin(54\text{\degree})} \\ x=\frac{72}{0.8090} \\ x=88.99 \\ \text{ Rounding to the nearest tenth} \\ x=89.0 \end{gathered}[/tex]
Therefore, the measure of the missing side is 89.
