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Finding the Fourth Proportional to 104.78, 156.75 and 90.12

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Solution

The fourth proportional to 104.78, 156.75 and 90.12 is: 134.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    104.78 : 156.75 = 90.12 : x
  2. Step 2: Convert to fraction form
    104.78/156.75 = 90.12/x
  3. Step 3: Cross multiply
    104.78x = 156.75 × 90.12
  4. Step 4: Simplify right side
    104.78x = 14,126.56
  5. Step 5: Solve for x
    x = 14,126.56/104.78
  6. Step 6: Final answer
    x = 134.82

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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.