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Finding the Fourth Proportional to 499.18, 688.40 and 312.61

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Solution

The fourth proportional to 499.18, 688.40 and 312.61 is: 431.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    499.18 : 688.40 = 312.61 : x
  2. Step 2: Convert to fraction form
    499.18/688.40 = 312.61/x
  3. Step 3: Cross multiply
    499.18x = 688.40 × 312.61
  4. Step 4: Simplify right side
    499.18x = 215,200.72
  5. Step 5: Solve for x
    x = 215,200.72/499.18
  6. Step 6: Final answer
    x = 431.11

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.