Question

What is the area of a trapezoid with a 7 ft base and a 6ft base that's 3 ft high

Answer 1

`\int\D\int\D_D1dA = \int\limits^3_0$ \int\limits^{7-(y)/(3) }_0 {1} \, dxdy\\=\int\limits^3_0 ({x}\left \{ {{y={7-(y)/(3) }} \atop {x=0}} \right.)dy\\ = \int\limits^3_0 {7-(y)/(3) } \, dy \\ = (7y-(y^2)/(6) )\left \{ {{y=3} \atop {x=0}} \right. \\= 19.5 ft^(2)`