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Finding the Fourth Proportional to 3.12, 4.31 and 1.91

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Solution

The fourth proportional to 3.12, 4.31 and 1.91 is: 2.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    3.12 : 4.31 = 1.91 : x
  2. Step 2: Convert to fraction form
    3.12/4.31 = 1.91/x
  3. Step 3: Cross multiply
    3.12x = 4.31 × 1.91
  4. Step 4: Simplify right side
    3.12x = 8.23
  5. Step 5: Solve for x
    x = 8.23/3.12
  6. Step 6: Final answer
    x = 2.64

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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.