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Finding the Fourth Proportional to 124.78, 172.17 and 72.32

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Solution

The fourth proportional to 124.78, 172.17 and 72.32 is: 99.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    124.78 : 172.17 = 72.32 : x
  2. Step 2: Convert to fraction form
    124.78/172.17 = 72.32/x
  3. Step 3: Cross multiply
    124.78x = 172.17 × 72.32
  4. Step 4: Simplify right side
    124.78x = 12,450.47
  5. Step 5: Solve for x
    x = 12,450.47/124.78
  6. Step 6: Final answer
    x = 99.78

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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.