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Finding the Fourth Proportional to 1,321.75, 1,982.64 and 409.75

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Solution

The fourth proportional to 1,321.75, 1,982.64 and 409.75 is: 614.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,321.75 : 1,982.64 = 409.75 : x
  2. Step 2: Convert to fraction form
    1,321.75/1,982.64 = 409.75/x
  3. Step 3: Cross multiply
    1,321.75x = 1,982.64 × 409.75
  4. Step 4: Simplify right side
    1,321.75x = 812,386.74
  5. Step 5: Solve for x
    x = 812,386.74/1,321.75
  6. Step 6: Final answer
    x = 614.63

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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.