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Finding the Fourth Proportional to 16.80, 21.90 and 16.80

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Solution

The fourth proportional to 16.80, 21.90 and 16.80 is: 21.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    16.80 : 21.90 = 16.80 : x
  2. Step 2: Convert to fraction form
    16.80/21.90 = 16.80/x
  3. Step 3: Cross multiply
    16.80x = 21.90 × 16.80
  4. Step 4: Simplify right side
    16.80x = 367.92
  5. Step 5: Solve for x
    x = 367.92/16.80
  6. Step 6: Final answer
    x = 21.90

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Why These Related Problems?

These problems maintain the same ratio (1.30) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.