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Finding the Fourth Proportional to 1,280.97, 1,767.71 and 721.42

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Solution

The fourth proportional to 1,280.97, 1,767.71 and 721.42 is: 995.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,280.97 : 1,767.71 = 721.42 : x
  2. Step 2: Convert to fraction form
    1,280.97/1,767.71 = 721.42/x
  3. Step 3: Cross multiply
    1,280.97x = 1,767.71 × 721.42
  4. Step 4: Simplify right side
    1,280.97x = 1,275,258.73
  5. Step 5: Solve for x
    x = 1,275,258.73/1,280.97
  6. Step 6: Final answer
    x = 995.54

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1.5x scale

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.