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Finding the Fourth Proportional to 155.70, 214.97 and 120.78

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Solution

The fourth proportional to 155.70, 214.97 and 120.78 is: 166.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    155.70 : 214.97 = 120.78 : x
  2. Step 2: Convert to fraction form
    155.70/214.97 = 120.78/x
  3. Step 3: Cross multiply
    155.70x = 214.97 × 120.78
  4. Step 4: Simplify right side
    155.70x = 25,963.47
  5. Step 5: Solve for x
    x = 25,963.47/155.70
  6. Step 6: Final answer
    x = 166.75

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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.