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Finding the Fourth Proportional to 25.71, 38.40 and 21.17

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Solution

The fourth proportional to 25.71, 38.40 and 21.17 is: 31.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    25.71 : 38.40 = 21.17 : x
  2. Step 2: Convert to fraction form
    25.71/38.40 = 21.17/x
  3. Step 3: Cross multiply
    25.71x = 38.40 × 21.17
  4. Step 4: Simplify right side
    25.71x = 812.74
  5. Step 5: Solve for x
    x = 812.74/25.71
  6. Step 6: Final answer
    x = 31.61

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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.