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Finding the Fourth Proportional to 211.11, 316.71 and 81.11

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Solution

The fourth proportional to 211.11, 316.71 and 81.11 is: 121.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    211.11 : 316.71 = 81.11 : x
  2. Step 2: Convert to fraction form
    211.11/316.71 = 81.11/x
  3. Step 3: Cross multiply
    211.11x = 316.71 × 81.11
  4. Step 4: Simplify right side
    211.11x = 25,686.76
  5. Step 5: Solve for x
    x = 25,686.76/211.11
  6. Step 6: Final answer
    x = 121.67

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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.