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Finding the Fourth Proportional to 1,380.70, 2,071.28 and 641.05

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Solution

The fourth proportional to 1,380.70, 2,071.28 and 641.05 is: 961.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,380.70 : 2,071.28 = 641.05 : x
  2. Step 2: Convert to fraction form
    1,380.70/2,071.28 = 641.05/x
  3. Step 3: Cross multiply
    1,380.70x = 2,071.28 × 641.05
  4. Step 4: Simplify right side
    1,380.70x = 1,327,794.04
  5. Step 5: Solve for x
    x = 1,327,794.04/1,380.70
  6. Step 6: Final answer
    x = 961.68

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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.