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Finding the Fourth Proportional to 25.72, 38.40 and 21.16

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Solution

The fourth proportional to 25.72, 38.40 and 21.16 is: 31.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    25.72 : 38.40 = 21.16 : x
  2. Step 2: Convert to fraction form
    25.72/38.40 = 21.16/x
  3. Step 3: Cross multiply
    25.72x = 38.40 × 21.16
  4. Step 4: Simplify right side
    25.72x = 812.54
  5. Step 5: Solve for x
    x = 812.54/25.72
  6. Step 6: Final answer
    x = 31.59

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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.