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Chapter 9: Solid Geometry
Worked Solutions 1.
216 in.2 The perimeter of the base, p, is found by multiplying 4 × 12 = 48.
Substitute:
1 pl units2 LA = 2 1 (48)(9) LA = 2
1: Multiply by 2
LA = 24(9)
Multiply:
LA = 216 in.2
Write the LA formula:
2.
384 in.3 1Bh units3 V= 3 1 (144)(8) Substitute (from previous): V = 3 1: V = (48)(8) Multiply 144 by 3 Use the V formula:
Multiply: 3.
4.
V = 384 in.3
84π cm2 First find B:
B = πr2 units2
Substitute:
B = π(6)2
Multiply:
B = 36π cm2
Now write the TA formula:
TA = πrl + B units2
Substitute:
TA = (6)(8)π + 36π
Multiply:
TA = 48π 6 + 36π
Add:
TA = 84π cm2
72π cm3
Substitute (from previous):
1 (B)(h) units3 V= 3 1 (36π)(6) V= 3
1: Multiply by 3
V = (36π)(2)
Multiply:
V = 72π cm3
Write the V formula: