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Finding the Fourth Proportional to 680.15, 1,020.25 and 419.99

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Solution

The fourth proportional to 680.15, 1,020.25 and 419.99 is: 629.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.15 : 1,020.25 = 419.99 : x
  2. Step 2: Convert to fraction form
    680.15/1,020.25 = 419.99/x
  3. Step 3: Cross multiply
    680.15x = 1,020.25 × 419.99
  4. Step 4: Simplify right side
    680.15x = 428,487.86
  5. Step 5: Solve for x
    x = 428,487.86/680.15
  6. Step 6: Final answer
    x = 629.99

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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.