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Finding the Fourth Proportional to 1,379.40, 2,069.48 and 649

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Solution

The fourth proportional to 1,379.40, 2,069.48 and 649 is: 973.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,379.40 : 2,069.48 = 649 : x
  2. Step 2: Convert to fraction form
    1,379.40/2,069.48 = 649/x
  3. Step 3: Cross multiply
    1,379.40x = 2,069.48 × 649
  4. Step 4: Simplify right side
    1,379.40x = 1,343,092.52
  5. Step 5: Solve for x
    x = 1,343,092.52/1,379.40
  6. Step 6: Final answer
    x = 973.68

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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.