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Finding the Fourth Proportional to 90.77, 125.21 and 55.78

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Solution

The fourth proportional to 90.77, 125.21 and 55.78 is: 76.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.77 : 125.21 = 55.78 : x
  2. Step 2: Convert to fraction form
    90.77/125.21 = 55.78/x
  3. Step 3: Cross multiply
    90.77x = 125.21 × 55.78
  4. Step 4: Simplify right side
    90.77x = 6,984.04
  5. Step 5: Solve for x
    x = 6,984.04/90.77
  6. Step 6: Final answer
    x = 76.95

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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.