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Finding the Fourth Proportional to 221.58, 305.85 and 138.63

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Solution

The fourth proportional to 221.58, 305.85 and 138.63 is: 191.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.58 : 305.85 = 138.63 : x
  2. Step 2: Convert to fraction form
    221.58/305.85 = 138.63/x
  3. Step 3: Cross multiply
    221.58x = 305.85 × 138.63
  4. Step 4: Simplify right side
    221.58x = 42,399.47
  5. Step 5: Solve for x
    x = 42,399.47/221.58
  6. Step 6: Final answer
    x = 191.35

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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.