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Finding the Fourth Proportional to 1,105.90, 1,660.20 and 612.70

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Solution

The fourth proportional to 1,105.90, 1,660.20 and 612.70 is: 919.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,105.90 : 1,660.20 = 612.70 : x
  2. Step 2: Convert to fraction form
    1,105.90/1,660.20 = 612.70/x
  3. Step 3: Cross multiply
    1,105.90x = 1,660.20 × 612.70
  4. Step 4: Simplify right side
    1,105.90x = 1,017,204.54
  5. Step 5: Solve for x
    x = 1,017,204.54/1,105.90
  6. Step 6: Final answer
    x = 919.80

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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.