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Finding the Fourth Proportional to 72.20, 99.61 and 47.65

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Solution

The fourth proportional to 72.20, 99.61 and 47.65 is: 65.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.20 : 99.61 = 47.65 : x
  2. Step 2: Convert to fraction form
    72.20/99.61 = 47.65/x
  3. Step 3: Cross multiply
    72.20x = 99.61 × 47.65
  4. Step 4: Simplify right side
    72.20x = 4,746.42
  5. Step 5: Solve for x
    x = 4,746.42/72.20
  6. Step 6: Final answer
    x = 65.74

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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.