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Finding the Fourth Proportional to 72.24, 99.78 and 63.15

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Solution

The fourth proportional to 72.24, 99.78 and 63.15 is: 87.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.24 : 99.78 = 63.15 : x
  2. Step 2: Convert to fraction form
    72.24/99.78 = 63.15/x
  3. Step 3: Cross multiply
    72.24x = 99.78 × 63.15
  4. Step 4: Simplify right side
    72.24x = 6,301.11
  5. Step 5: Solve for x
    x = 6,301.11/72.24
  6. Step 6: Final answer
    x = 87.22

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.