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Finding the Fourth Proportional to 1,213.80, 1,821.30 and 921.18

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Solution

The fourth proportional to 1,213.80, 1,821.30 and 921.18 is: 1,382.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,213.80 : 1,821.30 = 921.18 : x
  2. Step 2: Convert to fraction form
    1,213.80/1,821.30 = 921.18/x
  3. Step 3: Cross multiply
    1,213.80x = 1,821.30 × 921.18
  4. Step 4: Simplify right side
    1,213.80x = 1,677,745.13
  5. Step 5: Solve for x
    x = 1,677,745.13/1,213.80
  6. Step 6: Final answer
    x = 1,382.23

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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.