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Finding the Fourth Proportional to 159.81, 238.70 and 138.21

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Solution

The fourth proportional to 159.81, 238.70 and 138.21 is: 206.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    159.81 : 238.70 = 138.21 : x
  2. Step 2: Convert to fraction form
    159.81/238.70 = 138.21/x
  3. Step 3: Cross multiply
    159.81x = 238.70 × 138.21
  4. Step 4: Simplify right side
    159.81x = 32,990.04
  5. Step 5: Solve for x
    x = 32,990.04/159.81
  6. Step 6: Final answer
    x = 206.43

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.