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Finding the Fourth Proportional to 20.99, 28.86 and 18.36

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Solution

The fourth proportional to 20.99, 28.86 and 18.36 is: 25.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.99 : 28.86 = 18.36 : x
  2. Step 2: Convert to fraction form
    20.99/28.86 = 18.36/x
  3. Step 3: Cross multiply
    20.99x = 28.86 × 18.36
  4. Step 4: Simplify right side
    20.99x = 529.87
  5. Step 5: Solve for x
    x = 529.87/20.99
  6. Step 6: Final answer
    x = 25.25

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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.