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Finding the Fourth Proportional to 1,139.67, 1,709.55 and 409.05

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Solution

The fourth proportional to 1,139.67, 1,709.55 and 409.05 is: 613.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,139.67 : 1,709.55 = 409.05 : x
  2. Step 2: Convert to fraction form
    1,139.67/1,709.55 = 409.05/x
  3. Step 3: Cross multiply
    1,139.67x = 1,709.55 × 409.05
  4. Step 4: Simplify right side
    1,139.67x = 699,291.43
  5. Step 5: Solve for x
    x = 699,291.43/1,139.67
  6. Step 6: Final answer
    x = 613.59

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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.