Trigonometry Question 2

In right triangle $\triangle{ABC}$ shown below, the given lengths are in millimeters. What is $\sin{A}$ ?

\dfrac{4\sqrt{2}}{9}

\dfrac{4\sqrt{2}}{7}

\dfrac{7\sqrt{2}}{8}

\dfrac{7}{9}

\dfrac{9}{7}

Approach

Sine refers to the ratio of the opposite side to the hypotenuse. The side opposite to $\angle{A}$ is 7, and the hypotenuse is 9.

\text{opposite} : \text{hypotenuse}

= 7:9 = \boxed{\frac{7}{9}}