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Finding the Third Proportional to 15,120 and 21,000

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Solution

The third proportional to 15,120 and 21,000 is: 29,166.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    15,120 : 21,000 = 21,000 : x
  2. Step 2: Convert to fraction form
    15,120/21,000 = 21,000/x
  3. Step 3: Cross multiply
    15,120x = 21,000 × 21,000
  4. Step 4: Simplify right side
    15,120x = 441,000,000
  5. Step 5: Solve for x
    x = 441,000,000/15,120
  6. Step 6: Final answer
    x = 29,166.67

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.