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Finding the Fourth Proportional to 499.10, 689.20 and 312.91

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Solution

The fourth proportional to 499.10, 689.20 and 312.91 is: 432.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    499.10 : 689.20 = 312.91 : x
  2. Step 2: Convert to fraction form
    499.10/689.20 = 312.91/x
  3. Step 3: Cross multiply
    499.10x = 689.20 × 312.91
  4. Step 4: Simplify right side
    499.10x = 215,658.51
  5. Step 5: Solve for x
    x = 215,658.51/499.10
  6. Step 6: Final answer
    x = 432.09

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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.