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Finding the Fourth Proportional to 90.12, 124.38 and 70.86

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Solution

The fourth proportional to 90.12, 124.38 and 70.86 is: 97.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.12 : 124.38 = 70.86 : x
  2. Step 2: Convert to fraction form
    90.12/124.38 = 70.86/x
  3. Step 3: Cross multiply
    90.12x = 124.38 × 70.86
  4. Step 4: Simplify right side
    90.12x = 8,813.57
  5. Step 5: Solve for x
    x = 8,813.57/90.12
  6. Step 6: Final answer
    x = 97.80

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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.