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Finding the Fourth Proportional to 498.78, 687.51 and 393.69

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Solution

The fourth proportional to 498.78, 687.51 and 393.69 is: 542.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    498.78 : 687.51 = 393.69 : x
  2. Step 2: Convert to fraction form
    498.78/687.51 = 393.69/x
  3. Step 3: Cross multiply
    498.78x = 687.51 × 393.69
  4. Step 4: Simplify right side
    498.78x = 270,665.81
  5. Step 5: Solve for x
    x = 270,665.81/498.78
  6. Step 6: Final answer
    x = 542.66

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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.