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Finding the Fourth Proportional to 879.28, 1,213.30 and 646

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Solution

The fourth proportional to 879.28, 1,213.30 and 646 is: 891.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    879.28 : 1,213.30 = 646 : x
  2. Step 2: Convert to fraction form
    879.28/1,213.30 = 646/x
  3. Step 3: Cross multiply
    879.28x = 1,213.30 × 646
  4. Step 4: Simplify right side
    879.28x = 783,791.80
  5. Step 5: Solve for x
    x = 783,791.80/879.28
  6. Step 6: Final answer
    x = 891.40

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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.