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Finding the Fourth Proportional to 210.40, 290.41 and 121.86

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Solution

The fourth proportional to 210.40, 290.41 and 121.86 is: 168.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    210.40 : 290.41 = 121.86 : x
  2. Step 2: Convert to fraction form
    210.40/290.41 = 121.86/x
  3. Step 3: Cross multiply
    210.40x = 290.41 × 121.86
  4. Step 4: Simplify right side
    210.40x = 35,390.15
  5. Step 5: Solve for x
    x = 35,390.15/210.40
  6. Step 6: Final answer
    x = 168.20

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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.