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Finding the Fourth Proportional to 879.65, 1,213.65 and 617.21

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Solution

The fourth proportional to 879.65, 1,213.65 and 617.21 is: 851.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    879.65 : 1,213.65 = 617.21 : x
  2. Step 2: Convert to fraction form
    879.65/1,213.65 = 617.21/x
  3. Step 3: Cross multiply
    879.65x = 1,213.65 × 617.21
  4. Step 4: Simplify right side
    879.65x = 749,076.92
  5. Step 5: Solve for x
    x = 749,076.92/879.65
  6. Step 6: Final answer
    x = 851.56

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.