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Finding the Fourth Proportional to 21.42, 31.97 and 18.45

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Solution

The fourth proportional to 21.42, 31.97 and 18.45 is: 27.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    21.42 : 31.97 = 18.45 : x
  2. Step 2: Convert to fraction form
    21.42/31.97 = 18.45/x
  3. Step 3: Cross multiply
    21.42x = 31.97 × 18.45
  4. Step 4: Simplify right side
    21.42x = 589.89
  5. Step 5: Solve for x
    x = 589.89/21.42
  6. Step 6: Final answer
    x = 27.54

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.