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Finding the Fourth Proportional to 252.70, 378.90 and 90.31

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Solution

The fourth proportional to 252.70, 378.90 and 90.31 is: 135.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    252.70 : 378.90 = 90.31 : x
  2. Step 2: Convert to fraction form
    252.70/378.90 = 90.31/x
  3. Step 3: Cross multiply
    252.70x = 378.90 × 90.31
  4. Step 4: Simplify right side
    252.70x = 34,218.46
  5. Step 5: Solve for x
    x = 34,218.46/252.70
  6. Step 6: Final answer
    x = 135.41

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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.