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Finding the Fourth Proportional to 28.03, 38.64 and 21.81

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Solution

The fourth proportional to 28.03, 38.64 and 21.81 is: 30.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.03 : 38.64 = 21.81 : x
  2. Step 2: Convert to fraction form
    28.03/38.64 = 21.81/x
  3. Step 3: Cross multiply
    28.03x = 38.64 × 21.81
  4. Step 4: Simplify right side
    28.03x = 842.74
  5. Step 5: Solve for x
    x = 842.74/28.03
  6. Step 6: Final answer
    x = 30.07

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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.