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Finding the Fourth Proportional to 124.81, 172.18 and 81.13

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Solution

The fourth proportional to 124.81, 172.18 and 81.13 is: 111.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    124.81 : 172.18 = 81.13 : x
  2. Step 2: Convert to fraction form
    124.81/172.18 = 81.13/x
  3. Step 3: Cross multiply
    124.81x = 172.18 × 81.13
  4. Step 4: Simplify right side
    124.81x = 13,968.96
  5. Step 5: Solve for x
    x = 13,968.96/124.81
  6. Step 6: Final answer
    x = 111.92

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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.