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Finding the Fourth Proportional to 90.04, 134.91 and 78.61

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Solution

The fourth proportional to 90.04, 134.91 and 78.61 is: 117.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.04 : 134.91 = 78.61 : x
  2. Step 2: Convert to fraction form
    90.04/134.91 = 78.61/x
  3. Step 3: Cross multiply
    90.04x = 134.91 × 78.61
  4. Step 4: Simplify right side
    90.04x = 10,605.28
  5. Step 5: Solve for x
    x = 10,605.28/90.04
  6. Step 6: Final answer
    x = 117.78

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.