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Finding the Fourth Proportional to 90.76, 125.26 and 55.78

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Solution

The fourth proportional to 90.76, 125.26 and 55.78 is: 76.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.76 : 125.26 = 55.78 : x
  2. Step 2: Convert to fraction form
    90.76/125.26 = 55.78/x
  3. Step 3: Cross multiply
    90.76x = 125.26 × 55.78
  4. Step 4: Simplify right side
    90.76x = 6,986.79
  5. Step 5: Solve for x
    x = 6,986.79/90.76
  6. Step 6: Final answer
    x = 76.98

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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.