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Finding the Fourth Proportional to 20.84, 31.11 and 20.67

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Solution

The fourth proportional to 20.84, 31.11 and 20.67 is: 30.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.84 : 31.11 = 20.67 : x
  2. Step 2: Convert to fraction form
    20.84/31.11 = 20.67/x
  3. Step 3: Cross multiply
    20.84x = 31.11 × 20.67
  4. Step 4: Simplify right side
    20.84x = 643.04
  5. Step 5: Solve for x
    x = 643.04/20.84
  6. Step 6: Final answer
    x = 30.86

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.