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Finding the Fourth Proportional to 679.92, 1,019.20 and 315

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Solution

The fourth proportional to 679.92, 1,019.20 and 315 is: 472.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    679.92 : 1,019.20 = 315 : x
  2. Step 2: Convert to fraction form
    679.92/1,019.20 = 315/x
  3. Step 3: Cross multiply
    679.92x = 1,019.20 × 315
  4. Step 4: Simplify right side
    679.92x = 321,048
  5. Step 5: Solve for x
    x = 321,048/679.92
  6. Step 6: Final answer
    x = 472.18

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.