这是一份manchester曼切斯特大学ECON10061作业代写的成功案例
An elliptical platform is designed to have a surface area of 725 square feet. To give the desired form, the major axis must be $1 \frac{1}{2}$ times as long as the minor axis. Determine the dimensions of the major and minor axes.
Let $x=$ minor axis
$$
\begin{aligned}
&b=0.5 x \
&a=0.75 x
\end{aligned}
$$
$$
1.5 x=\text { major axis }
$$
\begin{aligned}
725 \mathrm{sq} \mathrm{} \mathrm{ft} &=3.1416(0.75 x)(0.5 x) \
725 \mathrm{sq} \mathrm{} \mathrm{ft} &=1.1781 x^{2} \
x^{2} & \approx 615.3977 \mathrm{sq} \mathrm{ft} \
x &=24.807 \mathrm{ft} \
\text { Minor axis } & \approx 24.8 \mathrm{ft} \text { Ans } \
\text { Major axis } & \approx 1.5(24.807 \mathrm{ft})=37.2 \mathrm{ft} \text { Ans }
\end{aligned}
ECON10061 COURSE NOTES ：
Find the area of the outside circle.
$A_{B}=0.7854 d^{2}$
$A_{B} \Rightarrow(0.7854)(4.00 \mathrm{in})^{2} \approx 12.5664 \mathrm{sq}$ in
Find the area of the hole.
$A_{B} \approx(0.7854)(3.40 \mathrm{in})^{2} \approx 9.079224 \mathrm{sq}$ in
Find the cross-sectional area.
$12.5664 \mathrm{sq}$ in $-9.079224 \mathrm{sq}$ in $\approx 3.487176 \mathrm{sq}$ in
Find the volume.
$V=3.487176 \mathrm{sq}$ in $\times 50.0$ in $\approx 174 \mathrm{cu}$ in Ans