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Finding the Fourth Proportional to 28.86, 39.83 and 21.57

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Solution

The fourth proportional to 28.86, 39.83 and 21.57 is: 29.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.86 : 39.83 = 21.57 : x
  2. Step 2: Convert to fraction form
    28.86/39.83 = 21.57/x
  3. Step 3: Cross multiply
    28.86x = 39.83 × 21.57
  4. Step 4: Simplify right side
    28.86x = 859.03
  5. Step 5: Solve for x
    x = 859.03/28.86
  6. Step 6: Final answer
    x = 29.77

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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.