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Finding the Fourth Proportional to 680.90, 1,020.54 and 518.90

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Solution

The fourth proportional to 680.90, 1,020.54 and 518.90 is: 777.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.90 : 1,020.54 = 518.90 : x
  2. Step 2: Convert to fraction form
    680.90/1,020.54 = 518.90/x
  3. Step 3: Cross multiply
    680.90x = 1,020.54 × 518.90
  4. Step 4: Simplify right side
    680.90x = 529,558.21
  5. Step 5: Solve for x
    x = 529,558.21/680.90
  6. Step 6: Final answer
    x = 777.73

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.