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Finding the Fourth Proportional to 221.39, 305.55 and 138.53

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Solution

The fourth proportional to 221.39, 305.55 and 138.53 is: 191.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.39 : 305.55 = 138.53 : x
  2. Step 2: Convert to fraction form
    221.39/305.55 = 138.53/x
  3. Step 3: Cross multiply
    221.39x = 305.55 × 138.53
  4. Step 4: Simplify right side
    221.39x = 42,326.31
  5. Step 5: Solve for x
    x = 42,326.31/221.39
  6. Step 6: Final answer
    x = 191.19

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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.