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Finding the Fourth Proportional to 252.50, 378.75 and 81.50

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Solution

The fourth proportional to 252.50, 378.75 and 81.50 is: 122.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    252.50 : 378.75 = 81.50 : x
  2. Step 2: Convert to fraction form
    252.50/378.75 = 81.50/x
  3. Step 3: Cross multiply
    252.50x = 378.75 × 81.50
  4. Step 4: Simplify right side
    252.50x = 30,868.13
  5. Step 5: Solve for x
    x = 30,868.13/252.50
  6. Step 6: Final answer
    x = 122.25

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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.