Answer:
let x=rate of the rowing team in still water
x+4=rate of the rowing team with current
x-4=rate of the rowing team against current
travel time=distance/rate
..
90%2F%28x%2B4%29=10%2F%28x-4%29
90x-360=10x+40
80x=400
x=5 rate of the rowing team in still water=5 mph
Use pythagora's theorem to test if it is a right triangle
c^2 = a^2 + b^2
65^2 = 52^2 + 43^2
4225 = 2704 + 1849
4225 =/= 4553
therefore it is not a right triangle as it does not comply to pythagora's theorem
100 centimeters in 1 meter