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Finding the Fourth Proportional to 1,370.87, 1,891.66 and 781.37

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Solution

The fourth proportional to 1,370.87, 1,891.66 and 781.37 is: 1,078.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,370.87 : 1,891.66 = 781.37 : x
  2. Step 2: Convert to fraction form
    1,370.87/1,891.66 = 781.37/x
  3. Step 3: Cross multiply
    1,370.87x = 1,891.66 × 781.37
  4. Step 4: Simplify right side
    1,370.87x = 1,478,086.37
  5. Step 5: Solve for x
    x = 1,478,086.37/1,370.87
  6. Step 6: Final answer
    x = 1,078.21

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.