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Finding the Fourth Proportional to 1,287.06, 1,930.87 and 409.61

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Solution

The fourth proportional to 1,287.06, 1,930.87 and 409.61 is: 614.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,287.06 : 1,930.87 = 409.61 : x
  2. Step 2: Convert to fraction form
    1,287.06/1,930.87 = 409.61/x
  3. Step 3: Cross multiply
    1,287.06x = 1,930.87 × 409.61
  4. Step 4: Simplify right side
    1,287.06x = 790,903.66
  5. Step 5: Solve for x
    x = 790,903.66/1,287.06
  6. Step 6: Final answer
    x = 614.50

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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.