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Finding the Fourth Proportional to 154.95, 212.78 and 138.57

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Solution

The fourth proportional to 154.95, 212.78 and 138.57 is: 190.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    154.95 : 212.78 = 138.57 : x
  2. Step 2: Convert to fraction form
    154.95/212.78 = 138.57/x
  3. Step 3: Cross multiply
    154.95x = 212.78 × 138.57
  4. Step 4: Simplify right side
    154.95x = 29,485.20
  5. Step 5: Solve for x
    x = 29,485.20/154.95
  6. Step 6: Final answer
    x = 190.29

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.