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Finding the Fourth Proportional to 28, 38.60 and 18.80

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Solution

The fourth proportional to 28, 38.60 and 18.80 is: 25.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    28 : 38.60 = 18.80 : x
  2. Step 2: Convert to fraction form
    28/38.60 = 18.80/x
  3. Step 3: Cross multiply
    28x = 38.60 × 18.80
  4. Step 4: Simplify right side
    28x = 725.68
  5. Step 5: Solve for x
    x = 725.68/28
  6. Step 6: Final answer
    x = 25.92

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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.