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Finding the Fourth Proportional to 305.78, 422.21 and 212.63

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Solution

The fourth proportional to 305.78, 422.21 and 212.63 is: 293.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    305.78 : 422.21 = 212.63 : x
  2. Step 2: Convert to fraction form
    305.78/422.21 = 212.63/x
  3. Step 3: Cross multiply
    305.78x = 422.21 × 212.63
  4. Step 4: Simplify right side
    305.78x = 89,772.93
  5. Step 5: Solve for x
    x = 89,772.93/305.78
  6. Step 6: Final answer
    x = 293.59

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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.