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Finding the Fourth Proportional to 124.74, 172.20 and 81.15

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Solution

The fourth proportional to 124.74, 172.20 and 81.15 is: 112.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    124.74 : 172.20 = 81.15 : x
  2. Step 2: Convert to fraction form
    124.74/172.20 = 81.15/x
  3. Step 3: Cross multiply
    124.74x = 172.20 × 81.15
  4. Step 4: Simplify right side
    124.74x = 13,974.03
  5. Step 5: Solve for x
    x = 13,974.03/124.74
  6. Step 6: Final answer
    x = 112.03

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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.