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Finding the Fourth Proportional to 816.20, 1,125.40 and 668.40

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Solution

The fourth proportional to 816.20, 1,125.40 and 668.40 is: 921.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    816.20 : 1,125.40 = 668.40 : x
  2. Step 2: Convert to fraction form
    816.20/1,125.40 = 668.40/x
  3. Step 3: Cross multiply
    816.20x = 1,125.40 × 668.40
  4. Step 4: Simplify right side
    816.20x = 752,217.36
  5. Step 5: Solve for x
    x = 752,217.36/816.20
  6. Step 6: Final answer
    x = 921.61

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.