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Finding the Fourth Proportional to 249.21, 343.96 and 138.72

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Solution

The fourth proportional to 249.21, 343.96 and 138.72 is: 191.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    249.21 : 343.96 = 138.72 : x
  2. Step 2: Convert to fraction form
    249.21/343.96 = 138.72/x
  3. Step 3: Cross multiply
    249.21x = 343.96 × 138.72
  4. Step 4: Simplify right side
    249.21x = 47,715.07
  5. Step 5: Solve for x
    x = 47,715.07/249.21
  6. Step 6: Final answer
    x = 191.47

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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.