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Finding the Fourth Proportional to 90.76, 125.16 and 77.68

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Solution

The fourth proportional to 90.76, 125.16 and 77.68 is: 107.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.76 : 125.16 = 77.68 : x
  2. Step 2: Convert to fraction form
    90.76/125.16 = 77.68/x
  3. Step 3: Cross multiply
    90.76x = 125.16 × 77.68
  4. Step 4: Simplify right side
    90.76x = 9,722.43
  5. Step 5: Solve for x
    x = 9,722.43/90.76
  6. Step 6: Final answer
    x = 107.12

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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.