# Water channel

The cross section of the water channel is a trapezoid. The width of the bottom is 19.7 m, the water surface width is 28.5 m, the side walls have a slope of 67°30' and 61°15'. Calculate how much water flows through the channel in 5 minutes if the water flow at rate 0.3 m/s.

Result

V =  19824.012 m3

#### Solution:

$c = 19.7 \ m \ \\ a = 28.5 \ m \ \\ x = a-c = 28.5-19.7 = \frac{ 44 }{ 5 } = 8.8 \ m \ \\ A = 67+30/60 = \frac{ 135 }{ 2 } = 67.5 \ \\ B = 61+15/60 = \frac{ 245 }{ 4 } = 61.25 \ \\ C = 180 - (A+B) = 180 - (67.5+61.25) = \frac{ 205 }{ 4 } = 51.25 \ \\ S_{ 1 } = x^2 \cdot \ \sin( A \rightarrow rad = A \cdot \ \frac{ \pi }{ 180 } \ rad = 40.2146853917 \ rad) \cdot \ \sin( B \rightarrow rad = B \cdot \ \frac{ \pi }{ 180 } \ rad = 40.2146853917 \ rad)/ (2 \cdot \ \sin( C \rightarrow rad = C \cdot \ \frac{ \pi }{ 180 } \ rad = 40.2146853917 \ rad)) \ \\ h = 2 \cdot \ S_{ 1 }/x = 2 \cdot \ 40.2147/8.8 \doteq 9.1397 \ \\ S_{ 2 } = c \cdot \ h = 19.7 \cdot \ 9.1397 \doteq 180.0521 \ m^2 \ \\ S = S_{ 1 }+S_{ 2 } = 40.2147+180.0521 \doteq 220.2668 \ m^2 \ \\ l = 5 \cdot \ 60 \cdot \ 0.3 = 90 \ m \ \\ V = l \cdot \ S = 90 \cdot \ 220.2668 \doteq 19824.012 = 19824.012 \ m^3$

Try calculation via our triangle calculator.

Leave us a comment of this math problem and its solution (i.e. if it is still somewhat unclear...):