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Finding the Fourth Proportional to 72.60, 108.90 and 61.80

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Solution

The fourth proportional to 72.60, 108.90 and 61.80 is: 92.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.60 : 108.90 = 61.80 : x
  2. Step 2: Convert to fraction form
    72.60/108.90 = 61.80/x
  3. Step 3: Cross multiply
    72.60x = 108.90 × 61.80
  4. Step 4: Simplify right side
    72.60x = 6,730.02
  5. Step 5: Solve for x
    x = 6,730.02/72.60
  6. Step 6: Final answer
    x = 92.70

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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.