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Finding the Fourth Proportional to 18.99, 28.50 and 12.21

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Solution

The fourth proportional to 18.99, 28.50 and 12.21 is: 18.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    18.99 : 28.50 = 12.21 : x
  2. Step 2: Convert to fraction form
    18.99/28.50 = 12.21/x
  3. Step 3: Cross multiply
    18.99x = 28.50 × 12.21
  4. Step 4: Simplify right side
    18.99x = 347.99
  5. Step 5: Solve for x
    x = 347.99/18.99
  6. Step 6: Final answer
    x = 18.32

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1.5x scale

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.