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Finding the Fourth Proportional to 209.02, 288.45 and 115.78

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Solution

The fourth proportional to 209.02, 288.45 and 115.78 is: 159.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.02 : 288.45 = 115.78 : x
  2. Step 2: Convert to fraction form
    209.02/288.45 = 115.78/x
  3. Step 3: Cross multiply
    209.02x = 288.45 × 115.78
  4. Step 4: Simplify right side
    209.02x = 33,396.74
  5. Step 5: Solve for x
    x = 33,396.74/209.02
  6. Step 6: Final answer
    x = 159.78

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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.