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Finding the Third Proportional to 15.12 and 31.90

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Solution

The third proportional to 15.12 and 31.90 is: 67.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    15.12 : 31.90 = 31.90 : x
  2. Step 2: Convert to fraction form
    15.12/31.90 = 31.90/x
  3. Step 3: Cross multiply
    15.12x = 31.90 × 31.90
  4. Step 4: Simplify right side
    15.12x = 1,017.51
  5. Step 5: Solve for x
    x = 1,017.51/15.12
  6. Step 6: Final answer
    x = 67.31

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Why These Related Problems?

These problems maintain the same ratio (2.11) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.