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Finding the Fourth Proportional to 31, 42.76 and 20.08

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Solution

The fourth proportional to 31, 42.76 and 20.08 is: 27.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    31 : 42.76 = 20.08 : x
  2. Step 2: Convert to fraction form
    31/42.76 = 20.08/x
  3. Step 3: Cross multiply
    31x = 42.76 × 20.08
  4. Step 4: Simplify right side
    31x = 858.62
  5. Step 5: Solve for x
    x = 858.62/31
  6. Step 6: Final answer
    x = 27.70

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1.5x scale

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.