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Finding the Fourth Proportional to 497.51, 686.90 and 311.28

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Solution

The fourth proportional to 497.51, 686.90 and 311.28 is: 429.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    497.51 : 686.90 = 311.28 : x
  2. Step 2: Convert to fraction form
    497.51/686.90 = 311.28/x
  3. Step 3: Cross multiply
    497.51x = 686.90 × 311.28
  4. Step 4: Simplify right side
    497.51x = 213,816.68
  5. Step 5: Solve for x
    x = 213,816.68/497.51
  6. Step 6: Final answer
    x = 429.78

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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.