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Finding the Fourth Proportional to 285.80, 428.10 and 255.40

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Solution

The fourth proportional to 285.80, 428.10 and 255.40 is: 382.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    285.80 : 428.10 = 255.40 : x
  2. Step 2: Convert to fraction form
    285.80/428.10 = 255.40/x
  3. Step 3: Cross multiply
    285.80x = 428.10 × 255.40
  4. Step 4: Simplify right side
    285.80x = 109,336.74
  5. Step 5: Solve for x
    x = 109,336.74/285.80
  6. Step 6: Final answer
    x = 382.56

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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.