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Finding the Fourth Proportional to 862.97, 1,191.20 and 639.71

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Solution

The fourth proportional to 862.97, 1,191.20 and 639.71 is: 883.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    862.97 : 1,191.20 = 639.71 : x
  2. Step 2: Convert to fraction form
    862.97/1,191.20 = 639.71/x
  3. Step 3: Cross multiply
    862.97x = 1,191.20 × 639.71
  4. Step 4: Simplify right side
    862.97x = 762,022.55
  5. Step 5: Solve for x
    x = 762,022.55/862.97
  6. Step 6: Final answer
    x = 883.02

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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.