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Finding the Fourth Proportional to 498.36, 687.78 and 393.20

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Solution

The fourth proportional to 498.36, 687.78 and 393.20 is: 542.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    498.36 : 687.78 = 393.20 : x
  2. Step 2: Convert to fraction form
    498.36/687.78 = 393.20/x
  3. Step 3: Cross multiply
    498.36x = 687.78 × 393.20
  4. Step 4: Simplify right side
    498.36x = 270,431.66
  5. Step 5: Solve for x
    x = 270,431.66/498.36
  6. Step 6: Final answer
    x = 542.64

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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.