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Finding the Fourth Proportional to 31.56, 43.53 and 21.18

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Solution

The fourth proportional to 31.56, 43.53 and 21.18 is: 29.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.56 : 43.53 = 21.18 : x
  2. Step 2: Convert to fraction form
    31.56/43.53 = 21.18/x
  3. Step 3: Cross multiply
    31.56x = 43.53 × 21.18
  4. Step 4: Simplify right side
    31.56x = 922.14
  5. Step 5: Solve for x
    x = 922.14/31.56
  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.