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Finding the Fourth Proportional to 639.60, 959.39 and 228.78

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Solution

The fourth proportional to 639.60, 959.39 and 228.78 is: 343.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.60 : 959.39 = 228.78 : x
  2. Step 2: Convert to fraction form
    639.60/959.39 = 228.78/x
  3. Step 3: Cross multiply
    639.60x = 959.39 × 228.78
  4. Step 4: Simplify right side
    639.60x = 219,489.24
  5. Step 5: Solve for x
    x = 219,489.24/639.60
  6. Step 6: Final answer
    x = 343.17

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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.