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Finding the Fourth Proportional to 1,121.31, 1,682.30 and 391.03

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Solution

The fourth proportional to 1,121.31, 1,682.30 and 391.03 is: 586.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,121.31 : 1,682.30 = 391.03 : x
  2. Step 2: Convert to fraction form
    1,121.31/1,682.30 = 391.03/x
  3. Step 3: Cross multiply
    1,121.31x = 1,682.30 × 391.03
  4. Step 4: Simplify right side
    1,121.31x = 657,826.54
  5. Step 5: Solve for x
    x = 657,826.54/1,121.31
  6. Step 6: Final answer
    x = 586.66

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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.