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Finding the Fourth Proportional to 209.12, 288.48 and 135.40

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Solution

The fourth proportional to 209.12, 288.48 and 135.40 is: 186.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.12 : 288.48 = 135.40 : x
  2. Step 2: Convert to fraction form
    209.12/288.48 = 135.40/x
  3. Step 3: Cross multiply
    209.12x = 288.48 × 135.40
  4. Step 4: Simplify right side
    209.12x = 39,060.19
  5. Step 5: Solve for x
    x = 39,060.19/209.12
  6. Step 6: Final answer
    x = 186.78

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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.