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Finding the Fourth Proportional to 135.50, 203.31 and 78.50

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Solution

The fourth proportional to 135.50, 203.31 and 78.50 is: 117.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    135.50 : 203.31 = 78.50 : x
  2. Step 2: Convert to fraction form
    135.50/203.31 = 78.50/x
  3. Step 3: Cross multiply
    135.50x = 203.31 × 78.50
  4. Step 4: Simplify right side
    135.50x = 15,959.84
  5. Step 5: Solve for x
    x = 15,959.84/135.50
  6. Step 6: Final answer
    x = 117.78

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.