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Finding the Fourth Proportional to 660.80, 991.20 and 651.20

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Solution

The fourth proportional to 660.80, 991.20 and 651.20 is: 976.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    660.80 : 991.20 = 651.20 : x
  2. Step 2: Convert to fraction form
    660.80/991.20 = 651.20/x
  3. Step 3: Cross multiply
    660.80x = 991.20 × 651.20
  4. Step 4: Simplify right side
    660.80x = 645,469.44
  5. Step 5: Solve for x
    x = 645,469.44/660.80
  6. Step 6: Final answer
    x = 976.80

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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.