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Finding the Fourth Proportional to 415.50, 621.72 and 258.78

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Solution

The fourth proportional to 415.50, 621.72 and 258.78 is: 387.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    415.50 : 621.72 = 258.78 : x
  2. Step 2: Convert to fraction form
    415.50/621.72 = 258.78/x
  3. Step 3: Cross multiply
    415.50x = 621.72 × 258.78
  4. Step 4: Simplify right side
    415.50x = 160,888.70
  5. Step 5: Solve for x
    x = 160,888.70/415.50
  6. Step 6: Final answer
    x = 387.22

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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.