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Finding the Fourth Proportional to 31.75, 43.78 and 20.67

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Solution

The fourth proportional to 31.75, 43.78 and 20.67 is: 28.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.75 : 43.78 = 20.67 : x
  2. Step 2: Convert to fraction form
    31.75/43.78 = 20.67/x
  3. Step 3: Cross multiply
    31.75x = 43.78 × 20.67
  4. Step 4: Simplify right side
    31.75x = 904.76
  5. Step 5: Solve for x
    x = 904.76/31.75
  6. Step 6: Final answer
    x = 28.50

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.