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Finding the Fourth Proportional to 211.85, 318.07 and 109.21

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Solution

The fourth proportional to 211.85, 318.07 and 109.21 is: 163.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    211.85 : 318.07 = 109.21 : x
  2. Step 2: Convert to fraction form
    211.85/318.07 = 109.21/x
  3. Step 3: Cross multiply
    211.85x = 318.07 × 109.21
  4. Step 4: Simplify right side
    211.85x = 34,734.29
  5. Step 5: Solve for x
    x = 34,734.29/211.85
  6. Step 6: Final answer
    x = 163.96

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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.