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Finding the Fourth Proportional to 158.56, 218.90 and 121.70

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Solution

The fourth proportional to 158.56, 218.90 and 121.70 is: 168.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    158.56 : 218.90 = 121.70 : x
  2. Step 2: Convert to fraction form
    158.56/218.90 = 121.70/x
  3. Step 3: Cross multiply
    158.56x = 218.90 × 121.70
  4. Step 4: Simplify right side
    158.56x = 26,640.98
  5. Step 5: Solve for x
    x = 26,640.98/158.56
  6. Step 6: Final answer
    x = 168.02

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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.