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Finding the Fourth Proportional to 18.99, 28.43 and 12.57

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Solution

The fourth proportional to 18.99, 28.43 and 12.57 is: 18.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    18.99 : 28.43 = 12.57 : x
  2. Step 2: Convert to fraction form
    18.99/28.43 = 12.57/x
  3. Step 3: Cross multiply
    18.99x = 28.43 × 12.57
  4. Step 4: Simplify right side
    18.99x = 357.37
  5. Step 5: Solve for x
    x = 357.37/18.99
  6. Step 6: Final answer
    x = 18.82

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.