$228cm^2$

$114cm^2$

$1224cm^2$

$122cm^2$

 $13.5\pi\ cm^{ }$ 

 $27\pi\ cm^{ }$ 

 $3\pi\ cm^{ }$ 

 $6\pi\ cm^{ }$ 

 $13.5\pi\ cm^2$ 

 $27\pi\ cm^2$ 

 $3\pi\ cm^2$ 

 $6\pi\ cm^2$ 

 $\frac{4}{3}\pi r^3+\pi r^2$ 

 $5\pi r^2$ 

 $2\pi r^3+\pi r^2$ 

 $3\pi r^2$ 

$288\pi\ cm^3$

$2304\pi\ cm^3$

$180\pi\ cm^3$

$720\pi\ cm^3$

㡳 $\times$ 高 $\div2$

$\sqrt{s\left(s-a\right)\left(s-b\right)\left(s-c\right)}$ ,當中 $s=\frac{a+b+c}{2}$

$\frac{1}{2}ab\sin\angle C$

$c^2=a^2+b^2-2ab\cos\angle C$