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Finding the Fourth Proportional to 498.30, 687.78 and 311.88

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Solution

The fourth proportional to 498.30, 687.78 and 311.88 is: 430.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    498.30 : 687.78 = 311.88 : x
  2. Step 2: Convert to fraction form
    498.30/687.78 = 311.88/x
  3. Step 3: Cross multiply
    498.30x = 687.78 × 311.88
  4. Step 4: Simplify right side
    498.30x = 214,504.83
  5. Step 5: Solve for x
    x = 214,504.83/498.30
  6. Step 6: Final answer
    x = 430.47

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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.