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Finding the Third Proportional to 21 and 28.50

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Solution

The third proportional to 21 and 28.50 is: 38.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    21 : 28.50 = 28.50 : x
  2. Step 2: Convert to fraction form
    21/28.50 = 28.50/x
  3. Step 3: Cross multiply
    21x = 28.50 × 28.50
  4. Step 4: Simplify right side
    21x = 812.25
  5. Step 5: Solve for x
    x = 812.25/21
  6. Step 6: Final answer
    x = 38.68

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Why These Related Problems?

These problems maintain the same ratio (1.36) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.