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Finding the Fourth Proportional to 19.90, 29.78 and 18.75

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Solution

The fourth proportional to 19.90, 29.78 and 18.75 is: 28.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    19.90 : 29.78 = 18.75 : x
  2. Step 2: Convert to fraction form
    19.90/29.78 = 18.75/x
  3. Step 3: Cross multiply
    19.90x = 29.78 × 18.75
  4. Step 4: Simplify right side
    19.90x = 558.38
  5. Step 5: Solve for x
    x = 558.38/19.90
  6. Step 6: Final answer
    x = 28.06

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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.