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Finding the Fourth Proportional to 782.20, 1,080.80 and 618.20

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Solution

The fourth proportional to 782.20, 1,080.80 and 618.20 is: 854.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    782.20 : 1,080.80 = 618.20 : x
  2. Step 2: Convert to fraction form
    782.20/1,080.80 = 618.20/x
  3. Step 3: Cross multiply
    782.20x = 1,080.80 × 618.20
  4. Step 4: Simplify right side
    782.20x = 668,150.56
  5. Step 5: Solve for x
    x = 668,150.56/782.20
  6. Step 6: Final answer
    x = 854.19

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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.