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Finding the Fourth Proportional to 499.12, 689.12 and 312.68

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Solution

The fourth proportional to 499.12, 689.12 and 312.68 is: 431.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    499.12 : 689.12 = 312.68 : x
  2. Step 2: Convert to fraction form
    499.12/689.12 = 312.68/x
  3. Step 3: Cross multiply
    499.12x = 689.12 × 312.68
  4. Step 4: Simplify right side
    499.12x = 215,474.04
  5. Step 5: Solve for x
    x = 215,474.04/499.12
  6. Step 6: Final answer
    x = 431.71

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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.