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Finding the Fourth Proportional to 72.24, 99.72 and 47.70

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Solution

The fourth proportional to 72.24, 99.72 and 47.70 is: 65.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.24 : 99.72 = 47.70 : x
  2. Step 2: Convert to fraction form
    72.24/99.72 = 47.70/x
  3. Step 3: Cross multiply
    72.24x = 99.72 × 47.70
  4. Step 4: Simplify right side
    72.24x = 4,756.64
  5. Step 5: Solve for x
    x = 4,756.64/72.24
  6. Step 6: Final answer
    x = 65.85

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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.