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Finding the Fourth Proportional to 782.80, 1,172.97 and 660.49

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Solution

The fourth proportional to 782.80, 1,172.97 and 660.49 is: 989.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    782.80 : 1,172.97 = 660.49 : x
  2. Step 2: Convert to fraction form
    782.80/1,172.97 = 660.49/x
  3. Step 3: Cross multiply
    782.80x = 1,172.97 × 660.49
  4. Step 4: Simplify right side
    782.80x = 774,734.96
  5. Step 5: Solve for x
    x = 774,734.96/782.80
  6. Step 6: Final answer
    x = 989.70

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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.