Question

A man moves on a cycle with a velocity of 4 km/hr. The rain appears to fall on him with a velocity of 3 km/hr vertically. The actual velocity of the rain is

Answer 1

$\sqrt{ ({4}^{2} } + {x }^{2} ) = 3 \\ {3 }^{2} = {4}^{2} + {x}^{2} \\ 9 = 16 + {x}^{2} \\ {x }^{2} + 16 - 9 = 0 \\ {x}^{2} + 15 = 0 \\ {x}^{2} = |-15| \\x = \sqrt{ | - 15| } \\ x = \sqrt{15}$