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Finding the Fourth Proportional to 124.79, 172.28 and 81.15

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Solution

The fourth proportional to 124.79, 172.28 and 81.15 is: 112.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    124.79 : 172.28 = 81.15 : x
  2. Step 2: Convert to fraction form
    124.79/172.28 = 81.15/x
  3. Step 3: Cross multiply
    124.79x = 172.28 × 81.15
  4. Step 4: Simplify right side
    124.79x = 13,980.12
  5. Step 5: Solve for x
    x = 13,980.12/124.79
  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.