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Finding the Fourth Proportional to 680.92, 1,020.57 and 391.76

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Solution

The fourth proportional to 680.92, 1,020.57 and 391.76 is: 587.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.92 : 1,020.57 = 391.76 : x
  2. Step 2: Convert to fraction form
    680.92/1,020.57 = 391.76/x
  3. Step 3: Cross multiply
    680.92x = 1,020.57 × 391.76
  4. Step 4: Simplify right side
    680.92x = 399,818.50
  5. Step 5: Solve for x
    x = 399,818.50/680.92
  6. Step 6: Final answer
    x = 587.17

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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.