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Finding the Fourth Proportional to 138.40, 191 and 76.24

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Solution

The fourth proportional to 138.40, 191 and 76.24 is: 105.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.40 : 191 = 76.24 : x
  2. Step 2: Convert to fraction form
    138.40/191 = 76.24/x
  3. Step 3: Cross multiply
    138.40x = 191 × 76.24
  4. Step 4: Simplify right side
    138.40x = 14,560.89
  5. Step 5: Solve for x
    x = 14,560.89/138.40
  6. Step 6: Final answer
    x = 105.21

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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.