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Finding the Fourth Proportional to 1,221.70, 1,685.73 and 724.09

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Solution

The fourth proportional to 1,221.70, 1,685.73 and 724.09 is: 999.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,221.70 : 1,685.73 = 724.09 : x
  2. Step 2: Convert to fraction form
    1,221.70/1,685.73 = 724.09/x
  3. Step 3: Cross multiply
    1,221.70x = 1,685.73 × 724.09
  4. Step 4: Simplify right side
    1,221.70x = 1,220,620.24
  5. Step 5: Solve for x
    x = 1,220,620.24/1,221.70
  6. Step 6: Final answer
    x = 999.12

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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.