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Finding the Fourth Proportional to 27.80, 38.40 and 21.41

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Solution

The fourth proportional to 27.80, 38.40 and 21.41 is: 29.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    27.80 : 38.40 = 21.41 : x
  2. Step 2: Convert to fraction form
    27.80/38.40 = 21.41/x
  3. Step 3: Cross multiply
    27.80x = 38.40 × 21.41
  4. Step 4: Simplify right side
    27.80x = 822.14
  5. Step 5: Solve for x
    x = 822.14/27.80
  6. Step 6: Final answer
    x = 29.57

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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.