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Finding the Fourth Proportional to 157.42, 217.20 and 138.88

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Solution

The fourth proportional to 157.42, 217.20 and 138.88 is: 191.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    157.42 : 217.20 = 138.88 : x
  2. Step 2: Convert to fraction form
    157.42/217.20 = 138.88/x
  3. Step 3: Cross multiply
    157.42x = 217.20 × 138.88
  4. Step 4: Simplify right side
    157.42x = 30,164.74
  5. Step 5: Solve for x
    x = 30,164.74/157.42
  6. Step 6: Final answer
    x = 191.62

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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.