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Finding the Fourth Proportional to 31.53, 43.51 and 21.18

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Solution

The fourth proportional to 31.53, 43.51 and 21.18 is: 29.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.53 : 43.51 = 21.18 : x
  2. Step 2: Convert to fraction form
    31.53/43.51 = 21.18/x
  3. Step 3: Cross multiply
    31.53x = 43.51 × 21.18
  4. Step 4: Simplify right side
    31.53x = 921.27
  5. Step 5: Solve for x
    x = 921.27/31.53
  6. Step 6: Final answer
    x = 29.22

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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.