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Finding the Fourth Proportional to 218.72, 328.05 and 72.47

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Solution

The fourth proportional to 218.72, 328.05 and 72.47 is: 108.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    218.72 : 328.05 = 72.47 : x
  2. Step 2: Convert to fraction form
    218.72/328.05 = 72.47/x
  3. Step 3: Cross multiply
    218.72x = 328.05 × 72.47
  4. Step 4: Simplify right side
    218.72x = 23,773.78
  5. Step 5: Solve for x
    x = 23,773.78/218.72
  6. Step 6: Final answer
    x = 108.70

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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.