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Finding the Fourth Proportional to 90.57, 124.92 and 72.15

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Solution

The fourth proportional to 90.57, 124.92 and 72.15 is: 99.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.57 : 124.92 = 72.15 : x
  2. Step 2: Convert to fraction form
    90.57/124.92 = 72.15/x
  3. Step 3: Cross multiply
    90.57x = 124.92 × 72.15
  4. Step 4: Simplify right side
    90.57x = 9,012.98
  5. Step 5: Solve for x
    x = 9,012.98/90.57
  6. Step 6: Final answer
    x = 99.51

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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.