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Finding the Fourth Proportional to 21.45, 29.59 and 15.21

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Solution

The fourth proportional to 21.45, 29.59 and 15.21 is: 20.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    21.45 : 29.59 = 15.21 : x
  2. Step 2: Convert to fraction form
    21.45/29.59 = 15.21/x
  3. Step 3: Cross multiply
    21.45x = 29.59 × 15.21
  4. Step 4: Simplify right side
    21.45x = 450.21
  5. Step 5: Solve for x
    x = 450.21/21.45
  6. Step 6: Final answer
    x = 20.99

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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.