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Finding the Fourth Proportional to 1,379.80, 2,069.70 and 1,120.60

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Solution

The fourth proportional to 1,379.80, 2,069.70 and 1,120.60 is: 1,680.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,379.80 : 2,069.70 = 1,120.60 : x
  2. Step 2: Convert to fraction form
    1,379.80/2,069.70 = 1,120.60/x
  3. Step 3: Cross multiply
    1,379.80x = 2,069.70 × 1,120.60
  4. Step 4: Simplify right side
    1,379.80x = 2,319,305.82
  5. Step 5: Solve for x
    x = 2,319,305.82/1,379.80
  6. Step 6: Final answer
    x = 1,680.90

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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.