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Finding the Fourth Proportional to 679.68, 1,020.20 and 398.34

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Solution

The fourth proportional to 679.68, 1,020.20 and 398.34 is: 597.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    679.68 : 1,020.20 = 398.34 : x
  2. Step 2: Convert to fraction form
    679.68/1,020.20 = 398.34/x
  3. Step 3: Cross multiply
    679.68x = 1,020.20 × 398.34
  4. Step 4: Simplify right side
    679.68x = 406,384.48
  5. Step 5: Solve for x
    x = 406,384.48/679.68
  6. Step 6: Final answer
    x = 597.91

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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.