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Finding the Third Proportional to 21 and 52

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Solution

The third proportional to 21 and 52 is: 128.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    21 : 52 = 52 : x
  2. Step 2: Convert to fraction form
    21/52 = 52/x
  3. Step 3: Cross multiply
    21x = 52 × 52
  4. Step 4: Simplify right side
    21x = 2,704
  5. Step 5: Solve for x
    x = 2,704/21
  6. Step 6: Final answer
    x = 128.76

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Why These Related Problems?

These problems maintain the same ratio (2.48) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.