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Finding the Fourth Proportional to 18.51, 27.72 and 12.78

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Solution

The fourth proportional to 18.51, 27.72 and 12.78 is: 19.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    18.51 : 27.72 = 12.78 : x
  2. Step 2: Convert to fraction form
    18.51/27.72 = 12.78/x
  3. Step 3: Cross multiply
    18.51x = 27.72 × 12.78
  4. Step 4: Simplify right side
    18.51x = 354.26
  5. Step 5: Solve for x
    x = 354.26/18.51
  6. Step 6: Final answer
    x = 19.14

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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.