## Thinking Mathematically (6th Edition)

$a \approx 42$
RECALL: In a right triangle, $\sin{A} = \dfrac{\text{length of opposite side}}{\text{length of hypotenuse}}$ $\cos{A} = \dfrac{\text{length of adjacent side}}{\text{length of hypotenuse}}$ $\tan{A} = \dfrac{\text{length of opposite side}}{\text{length of adjacent side}}$ Use the tangent formula above to obtain: $\tan{23^o} = \frac{a}{100}$ Multiply 100 on both sides of the equation to obtain: $100 \cdot \tan{23^o} = a$ Use a scientific calculator to obtain: $100 \cdot 0.4244748162 = a \\42.44748162 = a \\42 \approx a$