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Finding the Third Proportional to 21 and 47

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Solution

The third proportional to 21 and 47 is: 105.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    21 : 47 = 47 : x
  2. Step 2: Convert to fraction form
    21/47 = 47/x
  3. Step 3: Cross multiply
    21x = 47 × 47
  4. Step 4: Simplify right side
    21x = 2,209
  5. Step 5: Solve for x
    x = 2,209/21
  6. Step 6: Final answer
    x = 105.19

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Why These Related Problems?

These problems maintain the same ratio (2.24) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.