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Finding the Fourth Proportional to 90.64, 124.80 and 77.56

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Solution

The fourth proportional to 90.64, 124.80 and 77.56 is: 106.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.64 : 124.80 = 77.56 : x
  2. Step 2: Convert to fraction form
    90.64/124.80 = 77.56/x
  3. Step 3: Cross multiply
    90.64x = 124.80 × 77.56
  4. Step 4: Simplify right side
    90.64x = 9,679.49
  5. Step 5: Solve for x
    x = 9,679.49/90.64
  6. Step 6: Final answer
    x = 106.79

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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.