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Finding the Fourth Proportional to 28.02, 38.64 and 20.72

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Solution

The fourth proportional to 28.02, 38.64 and 20.72 is: 28.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.02 : 38.64 = 20.72 : x
  2. Step 2: Convert to fraction form
    28.02/38.64 = 20.72/x
  3. Step 3: Cross multiply
    28.02x = 38.64 × 20.72
  4. Step 4: Simplify right side
    28.02x = 800.62
  5. Step 5: Solve for x
    x = 800.62/28.02
  6. Step 6: Final answer
    x = 28.57

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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.