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Finding the Fourth Proportional to 879, 1,212.60 and 617.40

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Solution

The fourth proportional to 879, 1,212.60 and 617.40 is: 851.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    879 : 1,212.60 = 617.40 : x
  2. Step 2: Convert to fraction form
    879/1,212.60 = 617.40/x
  3. Step 3: Cross multiply
    879x = 1,212.60 × 617.40
  4. Step 4: Simplify right side
    879x = 748,659.24
  5. Step 5: Solve for x
    x = 748,659.24/879
  6. Step 6: Final answer
    x = 851.72

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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.