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Finding the Fourth Proportional to 28.57, 42.79 and 21.32

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Solution

The fourth proportional to 28.57, 42.79 and 21.32 is: 31.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.57 : 42.79 = 21.32 : x
  2. Step 2: Convert to fraction form
    28.57/42.79 = 21.32/x
  3. Step 3: Cross multiply
    28.57x = 42.79 × 21.32
  4. Step 4: Simplify right side
    28.57x = 912.28
  5. Step 5: Solve for x
    x = 912.28/28.57
  6. Step 6: Final answer
    x = 31.93

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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.