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Finding the Fourth Proportional to 498.80, 687.88 and 312.31

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Solution

The fourth proportional to 498.80, 687.88 and 312.31 is: 430.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    498.80 : 687.88 = 312.31 : x
  2. Step 2: Convert to fraction form
    498.80/687.88 = 312.31/x
  3. Step 3: Cross multiply
    498.80x = 687.88 × 312.31
  4. Step 4: Simplify right side
    498.80x = 214,829.30
  5. Step 5: Solve for x
    x = 214,829.30/498.80
  6. Step 6: Final answer
    x = 430.70

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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.