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Finding the Fourth Proportional to 209.81, 315.39 and 118.68

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Solution

The fourth proportional to 209.81, 315.39 and 118.68 is: 178.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.81 : 315.39 = 118.68 : x
  2. Step 2: Convert to fraction form
    209.81/315.39 = 118.68/x
  3. Step 3: Cross multiply
    209.81x = 315.39 × 118.68
  4. Step 4: Simplify right side
    209.81x = 37,430.49
  5. Step 5: Solve for x
    x = 37,430.49/209.81
  6. Step 6: Final answer
    x = 178.41

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.