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Finding the Fourth Proportional to 499.15, 688.91 and 312.72

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Solution

The fourth proportional to 499.15, 688.91 and 312.72 is: 431.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    499.15 : 688.91 = 312.72 : x
  2. Step 2: Convert to fraction form
    499.15/688.91 = 312.72/x
  3. Step 3: Cross multiply
    499.15x = 688.91 × 312.72
  4. Step 4: Simplify right side
    499.15x = 215,435.94
  5. Step 5: Solve for x
    x = 215,435.94/499.15
  6. Step 6: Final answer
    x = 431.61

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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.