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Finding the Fourth Proportional to 157.19, 217.18 and 138.81

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Solution

The fourth proportional to 157.19, 217.18 and 138.81 is: 191.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    157.19 : 217.18 = 138.81 : x
  2. Step 2: Convert to fraction form
    157.19/217.18 = 138.81/x
  3. Step 3: Cross multiply
    157.19x = 217.18 × 138.81
  4. Step 4: Simplify right side
    157.19x = 30,147.74
  5. Step 5: Solve for x
    x = 30,147.74/157.19
  6. Step 6: Final answer
    x = 191.79

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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.