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Finding the Fourth Proportional to 498.98, 688.38 and 312.40

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Solution

The fourth proportional to 498.98, 688.38 and 312.40 is: 430.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    498.98 : 688.38 = 312.40 : x
  2. Step 2: Convert to fraction form
    498.98/688.38 = 312.40/x
  3. Step 3: Cross multiply
    498.98x = 688.38 × 312.40
  4. Step 4: Simplify right side
    498.98x = 215,049.91
  5. Step 5: Solve for x
    x = 215,049.91/498.98
  6. Step 6: Final answer
    x = 430.98

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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.