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Finding the Fourth Proportional to 680.72, 1,021.12 and 578.72

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Solution

The fourth proportional to 680.72, 1,021.12 and 578.72 is: 868.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.72 : 1,021.12 = 578.72 : x
  2. Step 2: Convert to fraction form
    680.72/1,021.12 = 578.72/x
  3. Step 3: Cross multiply
    680.72x = 1,021.12 × 578.72
  4. Step 4: Simplify right side
    680.72x = 590,942.57
  5. Step 5: Solve for x
    x = 590,942.57/680.72
  6. Step 6: Final answer
    x = 868.11

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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.