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Finding the Fourth Proportional to 378.72, 522.70 and 221.34

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Solution

The fourth proportional to 378.72, 522.70 and 221.34 is: 305.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    378.72 : 522.70 = 221.34 : x
  2. Step 2: Convert to fraction form
    378.72/522.70 = 221.34/x
  3. Step 3: Cross multiply
    378.72x = 522.70 × 221.34
  4. Step 4: Simplify right side
    378.72x = 115,694.42
  5. Step 5: Solve for x
    x = 115,694.42/378.72
  6. Step 6: Final answer
    x = 305.49

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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.