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Finding the Fourth Proportional to 876, 1,209 and 643.44

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Solution

The fourth proportional to 876, 1,209 and 643.44 is: 888.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    876 : 1,209 = 643.44 : x
  2. Step 2: Convert to fraction form
    876/1,209 = 643.44/x
  3. Step 3: Cross multiply
    876x = 1,209 × 643.44
  4. Step 4: Simplify right side
    876x = 777,918.96
  5. Step 5: Solve for x
    x = 777,918.96/876
  6. Step 6: Final answer
    x = 888.04

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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.