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Finding the Fourth Proportional to 210.28, 290.20 and 121.78

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Solution

The fourth proportional to 210.28, 290.20 and 121.78 is: 168.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    210.28 : 290.20 = 121.78 : x
  2. Step 2: Convert to fraction form
    210.28/290.20 = 121.78/x
  3. Step 3: Cross multiply
    210.28x = 290.20 × 121.78
  4. Step 4: Simplify right side
    210.28x = 35,338.50
  5. Step 5: Solve for x
    x = 35,338.50/210.28
  6. Step 6: Final answer
    x = 168.06

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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.