Lesson 3C Composite Figures 607Volume of a Composite Figure
Find the volume of the composite
4 cm3 cm10 cmfigure. Round to the nearest tenth.
The figure is made up of a cylinder
and a cone.
V = πr^2 h + _^1
3
πr^2 hV = π · 52 · 3 + _^1
3
· π · 52 · 4
V ≈ 235.6 + 104.7 or 340.3
The volume of the composite figure is about 340.3 cubic centimeters.You can also find the surface area of composite figures by finding the
areas of the faces that make up the composite figure.Surface Area of a
Composite Figure
BASKETS Find the surface area of16 in.16 in.8 in.8 in.6 in.the staircase basket in Example 1.
The basket’s surface is made up
of three different polygons.16 in.16 in.8 in.8 in.8 in.16 in.6 in.8 in.6 in.
A = w + w A = w A = w
A = (8 · 16) + (8 · 8) A = 6 · 16 A = 6 · 8
A = 128 + 64 or 192 A = 96 A = 48
The total surface area of the basket is 2(192) + 2(96) + 4(48) or
768 square inches.b. Find the surface area of the2 ft3 ft
2 ft1 ft2 ft
composite figure.Volume Volume The formulas
for volume of cylinders
and cones are similar:
V = πr^2 h for cylinders and
V = 3 _^1 πr^2 h for cones.To make it easier to see
each face, sketch all of
the faces and label the
dimensions of each.Real-World Link
Basketry is the
weaving of vegetable
fibers into containers.
Baskets can be made
from any wood, vine,
leaf, or fiber that is
pliable.RRR604_610_C10_L3_895130.indd 607 1/4/10 3:05 PM