Question

a boat is traveling east across a river that is 112 meters wide at 8 meters per second. if the river has a northwest current of 5 meters per second, what is the resultant speed of the motorboat rounded to the nearest 10?

Answer 1

solution:

${c}^{2} = {a}^{2} + {b}^{2}$

${c}^{2} = {8}^{2} + {5}^{2}$

${c}^{2} = 64 + 25$

${c}^{2} = 89$

$c = \sqrt{89}$

$c = 9.4$

Answer 2

given:

boat speed= 8 m/s

river current= 5 m/s

to find:

the resultant speed of the motorboat rounded to the nearest 10.

solution:

use pythagorean theorem.

let the unknown be "x".

${a}^{2} = {b}^{2} + {c}^{2}$

${c}^{2} = \sqrt{ {a}^{2} + {b}^{2} }$

$x = \sqrt{ {8}^{2} + {5}^{2} }$

$x = \sqrt{64 + 25}$

$x = 9.4 \: m |s$

hence, the resultant speed of the motorboat is 9.4 m/s