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Finding the Fourth Proportional to 1,297.80, 1,947.90 and 1,115.40

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Solution

The fourth proportional to 1,297.80, 1,947.90 and 1,115.40 is: 1,674.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,297.80 : 1,947.90 = 1,115.40 : x
  2. Step 2: Convert to fraction form
    1,297.80/1,947.90 = 1,115.40/x
  3. Step 3: Cross multiply
    1,297.80x = 1,947.90 × 1,115.40
  4. Step 4: Simplify right side
    1,297.80x = 2,172,687.66
  5. Step 5: Solve for x
    x = 2,172,687.66/1,297.80
  6. Step 6: Final answer
    x = 1,674.13

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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.