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Finding the Fourth Proportional to 1,379.78, 2,070.14 and 649.40

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Solution

The fourth proportional to 1,379.78, 2,070.14 and 649.40 is: 974.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,379.78 : 2,070.14 = 649.40 : x
  2. Step 2: Convert to fraction form
    1,379.78/2,070.14 = 649.40/x
  3. Step 3: Cross multiply
    1,379.78x = 2,070.14 × 649.40
  4. Step 4: Simplify right side
    1,379.78x = 1,344,335.32
  5. Step 5: Solve for x
    x = 1,344,335.32/1,379.78
  6. Step 6: Final answer
    x = 974.31

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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.