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Finding the Fourth Proportional to 31.50, 43.47 and 20

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Solution

The fourth proportional to 31.50, 43.47 and 20 is: 27.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.50 : 43.47 = 20 : x
  2. Step 2: Convert to fraction form
    31.50/43.47 = 20/x
  3. Step 3: Cross multiply
    31.50x = 43.47 × 20
  4. Step 4: Simplify right side
    31.50x = 869.40
  5. Step 5: Solve for x
    x = 869.40/31.50
  6. Step 6: Final answer
    x = 27.60

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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.