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Finding the Fourth Proportional to 28.56, 42.80 and 21.33

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Solution

The fourth proportional to 28.56, 42.80 and 21.33 is: 31.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.56 : 42.80 = 21.33 : x
  2. Step 2: Convert to fraction form
    28.56/42.80 = 21.33/x
  3. Step 3: Cross multiply
    28.56x = 42.80 × 21.33
  4. Step 4: Simplify right side
    28.56x = 912.82
  5. Step 5: Solve for x
    x = 912.82/28.56
  6. Step 6: Final answer
    x = 31.96

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.