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Finding the Fourth Proportional to 101.21, 138.69 and 91.49

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Solution

The fourth proportional to 101.21, 138.69 and 91.49 is: 125.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    101.21 : 138.69 = 91.49 : x
  2. Step 2: Convert to fraction form
    101.21/138.69 = 91.49/x
  3. Step 3: Cross multiply
    101.21x = 138.69 × 91.49
  4. Step 4: Simplify right side
    101.21x = 12,688.05
  5. Step 5: Solve for x
    x = 12,688.05/101.21
  6. Step 6: Final answer
    x = 125.37

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.