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Finding the Fourth Proportional to 1,785.70, 2,679.09 and 811

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Solution

The fourth proportional to 1,785.70, 2,679.09 and 811 is: 1,216.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,785.70 : 2,679.09 = 811 : x
  2. Step 2: Convert to fraction form
    1,785.70/2,679.09 = 811/x
  3. Step 3: Cross multiply
    1,785.70x = 2,679.09 × 811
  4. Step 4: Simplify right side
    1,785.70x = 2,172,741.99
  5. Step 5: Solve for x
    x = 2,172,741.99/1,785.70
  6. Step 6: Final answer
    x = 1,216.75

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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.