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Finding the Fourth Proportional to 209.23, 288.77 and 121.90

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Solution

The fourth proportional to 209.23, 288.77 and 121.90 is: 168.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.23 : 288.77 = 121.90 : x
  2. Step 2: Convert to fraction form
    209.23/288.77 = 121.90/x
  3. Step 3: Cross multiply
    209.23x = 288.77 × 121.90
  4. Step 4: Simplify right side
    209.23x = 35,199.01
  5. Step 5: Solve for x
    x = 35,199.01/209.23
  6. Step 6: Final answer
    x = 168.24

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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.