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Finding the Fourth Proportional to 639.75, 959.06 and 274.78

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Solution

The fourth proportional to 639.75, 959.06 and 274.78 is: 411.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.75 : 959.06 = 274.78 : x
  2. Step 2: Convert to fraction form
    639.75/959.06 = 274.78/x
  3. Step 3: Cross multiply
    639.75x = 959.06 × 274.78
  4. Step 4: Simplify right side
    639.75x = 263,528.80
  5. Step 5: Solve for x
    x = 263,528.80/639.75
  6. Step 6: Final answer
    x = 411.92

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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.