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Finding the Fourth Proportional to 21.75, 30.05 and 18.10

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Solution

The fourth proportional to 21.75, 30.05 and 18.10 is: 25.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    21.75 : 30.05 = 18.10 : x
  2. Step 2: Convert to fraction form
    21.75/30.05 = 18.10/x
  3. Step 3: Cross multiply
    21.75x = 30.05 × 18.10
  4. Step 4: Simplify right side
    21.75x = 543.86
  5. Step 5: Solve for x
    x = 543.86/21.75
  6. Step 6: Final answer
    x = 25.01

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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.