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Finding the Fourth Proportional to 18.72, 25.80 and 18.40

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Solution

The fourth proportional to 18.72, 25.80 and 18.40 is: 25.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    18.72 : 25.80 = 18.40 : x
  2. Step 2: Convert to fraction form
    18.72/25.80 = 18.40/x
  3. Step 3: Cross multiply
    18.72x = 25.80 × 18.40
  4. Step 4: Simplify right side
    18.72x = 474.72
  5. Step 5: Solve for x
    x = 474.72/18.72
  6. Step 6: Final answer
    x = 25.36

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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.