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Finding the Fourth Proportional to 90.24, 124.20 and 76.40

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Solution

The fourth proportional to 90.24, 124.20 and 76.40 is: 105.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.24 : 124.20 = 76.40 : x
  2. Step 2: Convert to fraction form
    90.24/124.20 = 76.40/x
  3. Step 3: Cross multiply
    90.24x = 124.20 × 76.40
  4. Step 4: Simplify right side
    90.24x = 9,488.88
  5. Step 5: Solve for x
    x = 9,488.88/90.24
  6. Step 6: Final answer
    x = 105.15

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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.