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Finding the Fourth Proportional to 1,422.40, 2,131.81 and 641.58

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Solution

The fourth proportional to 1,422.40, 2,131.81 and 641.58 is: 961.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,422.40 : 2,131.81 = 641.58 : x
  2. Step 2: Convert to fraction form
    1,422.40/2,131.81 = 641.58/x
  3. Step 3: Cross multiply
    1,422.40x = 2,131.81 × 641.58
  4. Step 4: Simplify right side
    1,422.40x = 1,367,726.66
  5. Step 5: Solve for x
    x = 1,367,726.66/1,422.40
  6. Step 6: Final answer
    x = 961.56

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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.