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Finding the Fourth Proportional to 680.68, 1,019.40 and 391.24

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Solution

The fourth proportional to 680.68, 1,019.40 and 391.24 is: 585.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.68 : 1,019.40 = 391.24 : x
  2. Step 2: Convert to fraction form
    680.68/1,019.40 = 391.24/x
  3. Step 3: Cross multiply
    680.68x = 1,019.40 × 391.24
  4. Step 4: Simplify right side
    680.68x = 398,830.06
  5. Step 5: Solve for x
    x = 398,830.06/680.68
  6. Step 6: Final answer
    x = 585.93

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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.