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Finding the Fourth Proportional to 19.99, 27.55 and 15.90

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Solution

The fourth proportional to 19.99, 27.55 and 15.90 is: 21.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    19.99 : 27.55 = 15.90 : x
  2. Step 2: Convert to fraction form
    19.99/27.55 = 15.90/x
  3. Step 3: Cross multiply
    19.99x = 27.55 × 15.90
  4. Step 4: Simplify right side
    19.99x = 438.05
  5. Step 5: Solve for x
    x = 438.05/19.99
  6. Step 6: Final answer
    x = 21.91

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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.