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Finding the Fourth Proportional to 1,275, 1,912.38 and 409.32

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Solution

The fourth proportional to 1,275, 1,912.38 and 409.32 is: 613.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,275 : 1,912.38 = 409.32 : x
  2. Step 2: Convert to fraction form
    1,275/1,912.38 = 409.32/x
  3. Step 3: Cross multiply
    1,275x = 1,912.38 × 409.32
  4. Step 4: Simplify right side
    1,275x = 782,775.38
  5. Step 5: Solve for x
    x = 782,775.38/1,275
  6. Step 6: Final answer
    x = 613.94

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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.