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Finding the Fourth Proportional to 90.12, 124.20 and 84.72

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Solution

The fourth proportional to 90.12, 124.20 and 84.72 is: 116.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.12 : 124.20 = 84.72 : x
  2. Step 2: Convert to fraction form
    90.12/124.20 = 84.72/x
  3. Step 3: Cross multiply
    90.12x = 124.20 × 84.72
  4. Step 4: Simplify right side
    90.12x = 10,522.22
  5. Step 5: Solve for x
    x = 10,522.22/90.12
  6. Step 6: Final answer
    x = 116.76

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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.