## Algebra and Trigonometry 10th Edition

$|s|=126.49~miles~per~hour$ It is the total speed of the skydiver.
$|s|=\sqrt {s\cdot s}=\sqrt {(40i-120j)(40i-120j)}=\sqrt {1600+14400}=\sqrt {16000}=40\sqrt {10}\approx126.49$