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Finding the Fourth Proportional to 881.21, 1,321 and 387.11

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Solution

The fourth proportional to 881.21, 1,321 and 387.11 is: 580.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    881.21 : 1,321 = 387.11 : x
  2. Step 2: Convert to fraction form
    881.21/1,321 = 387.11/x
  3. Step 3: Cross multiply
    881.21x = 1,321 × 387.11
  4. Step 4: Simplify right side
    881.21x = 511,372.31
  5. Step 5: Solve for x
    x = 511,372.31/881.21
  6. Step 6: Final answer
    x = 580.31

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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.