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Finding the Fourth Proportional to 826.20, 1,139.40 and 660.42

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Solution

The fourth proportional to 826.20, 1,139.40 and 660.42 is: 910.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    826.20 : 1,139.40 = 660.42 : x
  2. Step 2: Convert to fraction form
    826.20/1,139.40 = 660.42/x
  3. Step 3: Cross multiply
    826.20x = 1,139.40 × 660.42
  4. Step 4: Simplify right side
    826.20x = 752,482.55
  5. Step 5: Solve for x
    x = 752,482.55/826.20
  6. Step 6: Final answer
    x = 910.78

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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.