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Finding the Fourth Proportional to 415.40, 623.10 and 285.80

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Solution

The fourth proportional to 415.40, 623.10 and 285.80 is: 428.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    415.40 : 623.10 = 285.80 : x
  2. Step 2: Convert to fraction form
    415.40/623.10 = 285.80/x
  3. Step 3: Cross multiply
    415.40x = 623.10 × 285.80
  4. Step 4: Simplify right side
    415.40x = 178,081.98
  5. Step 5: Solve for x
    x = 178,081.98/415.40
  6. Step 6: Final answer
    x = 428.70

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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.