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Tagged: Cylinder, Measurement, surface area
Calculate the surface area of a closed hemisphere with a radius of 5cm. Answer correct to the nearest cm.
Total surface area = half of the sphere plus the circular base
SA = ½ × 4 × π × 5^{2} + π × 5^{2}
SA = 235.619
= 236cm^{2}
A cylinder, open at one end, has a radius of 10cm and a height of 15cm. Find the surface area. $$SA=\pi\times10^2+2\times\pi\times10\times20$$^{ }= 1570.80cm^{2}
A sphere has a radius of 10cm. Find: a. the surface area b. the volume
a. Surface area = $$4\times\pi\times10^2$$^{ }= 1256.5cm^{}^{2} Use the surface area formula: $$4\pi r^2$$
b. Volume = $$\frac43\pi\times 10^3$$ = 4188.8cm^{3}Use the volume formula: $$\frac43\pi r^3$$