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Finding the Fourth Proportional to 498.30, 687.60 and 387.78

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Solution

The fourth proportional to 498.30, 687.60 and 387.78 is: 535.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    498.30 : 687.60 = 387.78 : x
  2. Step 2: Convert to fraction form
    498.30/687.60 = 387.78/x
  3. Step 3: Cross multiply
    498.30x = 687.60 × 387.78
  4. Step 4: Simplify right side
    498.30x = 266,637.53
  5. Step 5: Solve for x
    x = 266,637.53/498.30
  6. Step 6: Final answer
    x = 535.09

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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.