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Finding the Fourth Proportional to 879.78, 1,214.10 and 486.80

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Solution

The fourth proportional to 879.78, 1,214.10 and 486.80 is: 671.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    879.78 : 1,214.10 = 486.80 : x
  2. Step 2: Convert to fraction form
    879.78/1,214.10 = 486.80/x
  3. Step 3: Cross multiply
    879.78x = 1,214.10 × 486.80
  4. Step 4: Simplify right side
    879.78x = 591,022.36
  5. Step 5: Solve for x
    x = 591,022.36/879.78
  6. Step 6: Final answer
    x = 671.78

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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.