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Finding the Fourth Proportional to 415.12, 621.90 and 311.80

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Solution

The fourth proportional to 415.12, 621.90 and 311.80 is: 467.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    415.12 : 621.90 = 311.80 : x
  2. Step 2: Convert to fraction form
    415.12/621.90 = 311.80/x
  3. Step 3: Cross multiply
    415.12x = 621.90 × 311.80
  4. Step 4: Simplify right side
    415.12x = 193,908.42
  5. Step 5: Solve for x
    x = 193,908.42/415.12
  6. Step 6: Final answer
    x = 467.11

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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.