# The tractor

The tractor sows an average of 1.5 ha per hour. In how many hours does it sows a rectangular trapezoid field with the bases of 635m and 554m and a longer arm 207m?

Result

t =  7.55 h

#### Solution:

$a = 635 \ n \ \\ c = 554 \ m \ \\ b = 207 \ m \ \\ \ \\ h = \sqrt{ b^2 - (a-c)^2 } = \sqrt{ 207^2 - (635-554)^2 } = 72 \ \sqrt{ 7 } \ m \doteq 190.4941 \ m \ \\ \ \\ S = \dfrac{ a+c }{ 2 } \cdot \ h = \dfrac{ 635+554 }{ 2 } \cdot \ 190.4941 \doteq 113248.7391 \ m^2 \ \\ \ \\ S_{ 1 } = S \rightarrow ha = S / 10000 \ ha = 11.3248739119 \ ha \ \\ \ \\ t = S_{ 1 }/1.5 = 11.3249/1.5 \doteq 7.5499 = 7.55 \ \text { h }$

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