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Finding the Fourth Proportional to 31.41, 43.36 and 21.72

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Solution

The fourth proportional to 31.41, 43.36 and 21.72 is: 29.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.41 : 43.36 = 21.72 : x
  2. Step 2: Convert to fraction form
    31.41/43.36 = 21.72/x
  3. Step 3: Cross multiply
    31.41x = 43.36 × 21.72
  4. Step 4: Simplify right side
    31.41x = 941.72
  5. Step 5: Solve for x
    x = 941.72/31.41
  6. Step 6: Final answer
    x = 29.98

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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.