Answer:
Step-by-step explanation:
Sphere:
1) a) r = 7 cm
[tex]\sf \boxed{\text{Volume of sphere=$\dfrac{4}{3}\pi r^3$}}[/tex]
[tex]\sf =\dfrac{4}{3}*3.14*7*7*7\\\\= 1436 \ cm^3[/tex]
[tex]\sf \boxed{\text{\bf Surface area of sphere = $4\pi r^2$}}[/tex]
= 4*3.14 * 7 * 7
= 615.44 cm²
b) r= 8.4 cm
[tex]Volume = \dfrac{4}{3}\pi r^3[/tex]
[tex]\sf =\dfrac{4}{3}*\dfrac{22}{7}*8.4*8.4*8.4\\\\= 2483.7 \ cm^3[/tex]
Surface area = 4*3.14*8.4*8.4
= 887.04 cm²
Hemisphere:
a) r = 6 cm
[tex]\sf \boxed{\text{\bf Volume of hemisphere =$\dfrac{2}{3} \pi r^3$}}[/tex]
[tex]\sf =\dfrac{2}{3}*3.14*6*6*6\\\\= 452.16 \ cm^3[/tex]
[tex]\sf \boxed{\text{\bf Surface area of hemisphere=3 \pi r^2}}[/tex][tex]\sf \boxed{\text{\bf Surface area of hemisphere = $3 \pi r^2$}}[/tex]
= 3 * 3.14 * 6 * 6
= 339.12 cm²
