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Finding the Fourth Proportional to 1,220.62, 1,684.48 and 689.61

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Solution

The fourth proportional to 1,220.62, 1,684.48 and 689.61 is: 951.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,220.62 : 1,684.48 = 689.61 : x
  2. Step 2: Convert to fraction form
    1,220.62/1,684.48 = 689.61/x
  3. Step 3: Cross multiply
    1,220.62x = 1,684.48 × 689.61
  4. Step 4: Simplify right side
    1,220.62x = 1,161,632.53
  5. Step 5: Solve for x
    x = 1,161,632.53/1,220.62
  6. Step 6: Final answer
    x = 951.68

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.