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Finding the Fourth Proportional to 90.28, 134.87 and 78.22

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Solution

The fourth proportional to 90.28, 134.87 and 78.22 is: 116.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.28 : 134.87 = 78.22 : x
  2. Step 2: Convert to fraction form
    90.28/134.87 = 78.22/x
  3. Step 3: Cross multiply
    90.28x = 134.87 × 78.22
  4. Step 4: Simplify right side
    90.28x = 10,549.53
  5. Step 5: Solve for x
    x = 10,549.53/90.28
  6. Step 6: Final answer
    x = 116.85

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.