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Finding the Fourth Proportional to 879.90, 1,214.55 and 618.78

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Solution

The fourth proportional to 879.90, 1,214.55 and 618.78 is: 854.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    879.90 : 1,214.55 = 618.78 : x
  2. Step 2: Convert to fraction form
    879.90/1,214.55 = 618.78/x
  3. Step 3: Cross multiply
    879.90x = 1,214.55 × 618.78
  4. Step 4: Simplify right side
    879.90x = 751,539.25
  5. Step 5: Solve for x
    x = 751,539.25/879.90
  6. Step 6: Final answer
    x = 854.12

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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.