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Finding the Fourth Proportional to 21.42, 32.13 and 7.91

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Solution

The fourth proportional to 21.42, 32.13 and 7.91 is: 11.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    21.42 : 32.13 = 7.91 : x
  2. Step 2: Convert to fraction form
    21.42/32.13 = 7.91/x
  3. Step 3: Cross multiply
    21.42x = 32.13 × 7.91
  4. Step 4: Simplify right side
    21.42x = 253.99
  5. Step 5: Solve for x
    x = 253.99/21.42
  6. Step 6: Final answer
    x = 11.86

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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.