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Finding the Fourth Proportional to 680.03, 1,019.21 and 387.78

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Solution

The fourth proportional to 680.03, 1,019.21 and 387.78 is: 581.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.03 : 1,019.21 = 387.78 : x
  2. Step 2: Convert to fraction form
    680.03/1,019.21 = 387.78/x
  3. Step 3: Cross multiply
    680.03x = 1,019.21 × 387.78
  4. Step 4: Simplify right side
    680.03x = 395,223.49
  5. Step 5: Solve for x
    x = 395,223.49/680.03
  6. Step 6: Final answer
    x = 581.19

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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.