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Finding the Fourth Proportional to 153.78, 212.10 and 122.70

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Solution

The fourth proportional to 153.78, 212.10 and 122.70 is: 169.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    153.78 : 212.10 = 122.70 : x
  2. Step 2: Convert to fraction form
    153.78/212.10 = 122.70/x
  3. Step 3: Cross multiply
    153.78x = 212.10 × 122.70
  4. Step 4: Simplify right side
    153.78x = 26,024.67
  5. Step 5: Solve for x
    x = 26,024.67/153.78
  6. Step 6: Final answer
    x = 169.23

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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.