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Finding the Fourth Proportional to 252.15, 378.18 and 81.15

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Solution

The fourth proportional to 252.15, 378.18 and 81.15 is: 121.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    252.15 : 378.18 = 81.15 : x
  2. Step 2: Convert to fraction form
    252.15/378.18 = 81.15/x
  3. Step 3: Cross multiply
    252.15x = 378.18 × 81.15
  4. Step 4: Simplify right side
    252.15x = 30,687.01
  5. Step 5: Solve for x
    x = 30,687.01/252.15
  6. Step 6: Final answer
    x = 121.70

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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.