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Finding the Fourth Proportional to 538.78, 742.89 and 499.90

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Solution

The fourth proportional to 538.78, 742.89 and 499.90 is: 689.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    538.78 : 742.89 = 499.90 : x
  2. Step 2: Convert to fraction form
    538.78/742.89 = 499.90/x
  3. Step 3: Cross multiply
    538.78x = 742.89 × 499.90
  4. Step 4: Simplify right side
    538.78x = 371,370.71
  5. Step 5: Solve for x
    x = 371,370.71/538.78
  6. Step 6: Final answer
    x = 689.28

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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.