Geometry, area, and volume

area of a triangle of base band height h	$=\frac{1}{2}bh$
circumference of a circle of radius r	$=2\pi r$
area of a circle of radius r	$=\pi r^{2}$
surface area of a sphere of radius r	$=4\pi r^{2}$
volume of a sphere of radius r	$=\frac{4}{3}\pi r^{3}$

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