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Finding the Fourth Proportional to 879, 1,212.35 and 643.83

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Solution

The fourth proportional to 879, 1,212.35 and 643.83 is: 887.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    879 : 1,212.35 = 643.83 : x
  2. Step 2: Convert to fraction form
    879/1,212.35 = 643.83/x
  3. Step 3: Cross multiply
    879x = 1,212.35 × 643.83
  4. Step 4: Simplify right side
    879x = 780,544.08
  5. Step 5: Solve for x
    x = 780,544.08/879
  6. Step 6: Final answer
    x = 887.99

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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.