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Finding the Fourth Proportional to 378.66, 522.39 and 221.28

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Solution

The fourth proportional to 378.66, 522.39 and 221.28 is: 305.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    378.66 : 522.39 = 221.28 : x
  2. Step 2: Convert to fraction form
    378.66/522.39 = 221.28/x
  3. Step 3: Cross multiply
    378.66x = 522.39 × 221.28
  4. Step 4: Simplify right side
    378.66x = 115,594.46
  5. Step 5: Solve for x
    x = 115,594.46/378.66
  6. Step 6: Final answer
    x = 305.27

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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.