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Finding the Fourth Proportional to 72.80, 108.96 and 40.64

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Solution

The fourth proportional to 72.80, 108.96 and 40.64 is: 60.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.80 : 108.96 = 40.64 : x
  2. Step 2: Convert to fraction form
    72.80/108.96 = 40.64/x
  3. Step 3: Cross multiply
    72.80x = 108.96 × 40.64
  4. Step 4: Simplify right side
    72.80x = 4,428.13
  5. Step 5: Solve for x
    x = 4,428.13/72.80
  6. Step 6: Final answer
    x = 60.83

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.