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Finding the Fourth Proportional to 20.81, 28.65 and 18.50

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Solution

The fourth proportional to 20.81, 28.65 and 18.50 is: 25.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.81 : 28.65 = 18.50 : x
  2. Step 2: Convert to fraction form
    20.81/28.65 = 18.50/x
  3. Step 3: Cross multiply
    20.81x = 28.65 × 18.50
  4. Step 4: Simplify right side
    20.81x = 530.03
  5. Step 5: Solve for x
    x = 530.03/20.81
  6. Step 6: Final answer
    x = 25.47

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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.