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Finding the Fourth Proportional to 153.70, 212.06 and 138.90

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Solution

The fourth proportional to 153.70, 212.06 and 138.90 is: 191.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    153.70 : 212.06 = 138.90 : x
  2. Step 2: Convert to fraction form
    153.70/212.06 = 138.90/x
  3. Step 3: Cross multiply
    153.70x = 212.06 × 138.90
  4. Step 4: Simplify right side
    153.70x = 29,455.57
  5. Step 5: Solve for x
    x = 29,455.57/153.70
  6. Step 6: Final answer
    x = 191.64

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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.