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Finding the Fourth Proportional to 1,259.87, 1,739.40 and 811.90

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Solution

The fourth proportional to 1,259.87, 1,739.40 and 811.90 is: 1,120.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,259.87 : 1,739.40 = 811.90 : x
  2. Step 2: Convert to fraction form
    1,259.87/1,739.40 = 811.90/x
  3. Step 3: Cross multiply
    1,259.87x = 1,739.40 × 811.90
  4. Step 4: Simplify right side
    1,259.87x = 1,412,215.67
  5. Step 5: Solve for x
    x = 1,412,215.67/1,259.87
  6. Step 6: Final answer
    x = 1,120.92

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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.