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Finding the Fourth Proportional to 124.78, 172.38 and 83.31

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Solution

The fourth proportional to 124.78, 172.38 and 83.31 is: 115.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    124.78 : 172.38 = 83.31 : x
  2. Step 2: Convert to fraction form
    124.78/172.38 = 83.31/x
  3. Step 3: Cross multiply
    124.78x = 172.38 × 83.31
  4. Step 4: Simplify right side
    124.78x = 14,360.56
  5. Step 5: Solve for x
    x = 14,360.56/124.78
  6. Step 6: Final answer
    x = 115.09

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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.