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Finding the Fourth Proportional to 1,379.80, 1,903.91 and 820.26

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Solution

The fourth proportional to 1,379.80, 1,903.91 and 820.26 is: 1,131.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,379.80 : 1,903.91 = 820.26 : x
  2. Step 2: Convert to fraction form
    1,379.80/1,903.91 = 820.26/x
  3. Step 3: Cross multiply
    1,379.80x = 1,903.91 × 820.26
  4. Step 4: Simplify right side
    1,379.80x = 1,561,691.70
  5. Step 5: Solve for x
    x = 1,561,691.70/1,379.80
  6. Step 6: Final answer
    x = 1,131.82

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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.