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Finding the Fourth Proportional to 1,389.40, 2,083.20 and 660.04

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Solution

The fourth proportional to 1,389.40, 2,083.20 and 660.04 is: 989.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,389.40 : 2,083.20 = 660.04 : x
  2. Step 2: Convert to fraction form
    1,389.40/2,083.20 = 660.04/x
  3. Step 3: Cross multiply
    1,389.40x = 2,083.20 × 660.04
  4. Step 4: Simplify right side
    1,389.40x = 1,374,995.33
  5. Step 5: Solve for x
    x = 1,374,995.33/1,389.40
  6. Step 6: Final answer
    x = 989.63

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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.