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Finding the Fourth Proportional to 1,221.03, 1,684.91 and 689.87

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Solution

The fourth proportional to 1,221.03, 1,684.91 and 689.87 is: 951.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,221.03 : 1,684.91 = 689.87 : x
  2. Step 2: Convert to fraction form
    1,221.03/1,684.91 = 689.87/x
  3. Step 3: Cross multiply
    1,221.03x = 1,684.91 × 689.87
  4. Step 4: Simplify right side
    1,221.03x = 1,162,356.99
  5. Step 5: Solve for x
    x = 1,162,356.99/1,221.03
  6. Step 6: Final answer
    x = 951.95

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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.