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Finding the Fourth Proportional to 126.15, 189.43 and 78.36

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Solution

The fourth proportional to 126.15, 189.43 and 78.36 is: 117.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    126.15 : 189.43 = 78.36 : x
  2. Step 2: Convert to fraction form
    126.15/189.43 = 78.36/x
  3. Step 3: Cross multiply
    126.15x = 189.43 × 78.36
  4. Step 4: Simplify right side
    126.15x = 14,843.73
  5. Step 5: Solve for x
    x = 14,843.73/126.15
  6. Step 6: Final answer
    x = 117.67

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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.