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Finding the Fourth Proportional to 28.64, 42.91 and 20.51

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Solution

The fourth proportional to 28.64, 42.91 and 20.51 is: 30.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.64 : 42.91 = 20.51 : x
  2. Step 2: Convert to fraction form
    28.64/42.91 = 20.51/x
  3. Step 3: Cross multiply
    28.64x = 42.91 × 20.51
  4. Step 4: Simplify right side
    28.64x = 879.77
  5. Step 5: Solve for x
    x = 879.77/28.64
  6. Step 6: Final answer
    x = 30.72

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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.