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Finding the Fourth Proportional to 90.52, 135.76 and 78.76

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Solution

The fourth proportional to 90.52, 135.76 and 78.76 is: 118.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.52 : 135.76 = 78.76 : x
  2. Step 2: Convert to fraction form
    90.52/135.76 = 78.76/x
  3. Step 3: Cross multiply
    90.52x = 135.76 × 78.76
  4. Step 4: Simplify right side
    90.52x = 10,692.46
  5. Step 5: Solve for x
    x = 10,692.46/90.52
  6. Step 6: Final answer
    x = 118.12

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.