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Finding the Fourth Proportional to 209.95, 315.21 and 118.81

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Solution

The fourth proportional to 209.95, 315.21 and 118.81 is: 178.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.95 : 315.21 = 118.81 : x
  2. Step 2: Convert to fraction form
    209.95/315.21 = 118.81/x
  3. Step 3: Cross multiply
    209.95x = 315.21 × 118.81
  4. Step 4: Simplify right side
    209.95x = 37,450.10
  5. Step 5: Solve for x
    x = 37,450.10/209.95
  6. Step 6: Final answer
    x = 178.38

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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.