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Finding the Fourth Proportional to 21.02, 31.32 and 19.86

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Solution

The fourth proportional to 21.02, 31.32 and 19.86 is: 29.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    21.02 : 31.32 = 19.86 : x
  2. Step 2: Convert to fraction form
    21.02/31.32 = 19.86/x
  3. Step 3: Cross multiply
    21.02x = 31.32 × 19.86
  4. Step 4: Simplify right side
    21.02x = 622.02
  5. Step 5: Solve for x
    x = 622.02/21.02
  6. Step 6: Final answer
    x = 29.59

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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.