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Finding the Fourth Proportional to 243.69, 336.26 and 138.78

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Solution

The fourth proportional to 243.69, 336.26 and 138.78 is: 191.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    243.69 : 336.26 = 138.78 : x
  2. Step 2: Convert to fraction form
    243.69/336.26 = 138.78/x
  3. Step 3: Cross multiply
    243.69x = 336.26 × 138.78
  4. Step 4: Simplify right side
    243.69x = 46,666.16
  5. Step 5: Solve for x
    x = 46,666.16/243.69
  6. Step 6: Final answer
    x = 191.50

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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.