Digits, Grade 8, Volume 1, Homework Helper

5-6: Additional Problem Solving

Part 1

Example Finding Surface Areas of Composite 3-D Figures

The party favors have the shape of 2 identical cones attached at their bases. The base radius is 2 in. To the nearest cubic inch, how much confetti do you need to fill each party favor? Use 3.14 for π.

A party favor with total length of 10 inches.

Solution

Find the amount of confetti needed to fill the party favor by calculating the volume of one cone and doubling it.

  • Step 1 Find the volume of one cone.

    Since the double cone is 10 in. long, the height of one cone is 5 in.

    table with 4 rows and 2 columns , row1 column 1 , v , column 2 equals , 1 third , pi , r squared , h , row2 column 1 , , column 2 equals , 1 third , pi . open 2 close squared . open 5 close , row3 column 1 , , column 2 equals , 1 third , pi open 20 close , row4 column 1 , almost equal to 21 , end table


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Table of Contents

Digits, Grade 8, Volume 1, Homework Helper Unit A: Number and Operations Unit B: Proportionality Unit C: Expressions, Equations, and Relationships English/Spanish Glossary Formulas Math Symbols Formulas Measures Properties