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Finding the Fourth Proportional to 21.72, 30.00 and 15.59

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Solution

The fourth proportional to 21.72, 30.00 and 15.59 is: 21.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    21.72 : 30.00 = 15.59 : x
  2. Step 2: Convert to fraction form
    21.72/30.00 = 15.59/x
  3. Step 3: Cross multiply
    21.72x = 30.00 × 15.59
  4. Step 4: Simplify right side
    21.72x = 467.72
  5. Step 5: Solve for x
    x = 467.72/21.72
  6. Step 6: Final answer
    x = 21.53

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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.