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Finding the Fourth Proportional to 498.78, 688.20 and 380.70

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Solution

The fourth proportional to 498.78, 688.20 and 380.70 is: 525.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    498.78 : 688.20 = 380.70 : x
  2. Step 2: Convert to fraction form
    498.78/688.20 = 380.70/x
  3. Step 3: Cross multiply
    498.78x = 688.20 × 380.70
  4. Step 4: Simplify right side
    498.78x = 261,997.74
  5. Step 5: Solve for x
    x = 261,997.74/498.78
  6. Step 6: Final answer
    x = 525.28

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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.