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Finding the Fourth Proportional to 90.85, 125.30 and 77.11

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Solution

The fourth proportional to 90.85, 125.30 and 77.11 is: 106.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.85 : 125.30 = 77.11 : x
  2. Step 2: Convert to fraction form
    90.85/125.30 = 77.11/x
  3. Step 3: Cross multiply
    90.85x = 125.30 × 77.11
  4. Step 4: Simplify right side
    90.85x = 9,661.88
  5. Step 5: Solve for x
    x = 9,661.88/90.85
  6. Step 6: Final answer
    x = 106.35

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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.