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Finding the Third Proportional to 7,788 and 12,840

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Solution

The third proportional to 7,788 and 12,840 is: 21,169.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    7,788 : 12,840 = 12,840 : x
  2. Step 2: Convert to fraction form
    7,788/12,840 = 12,840/x
  3. Step 3: Cross multiply
    7,788x = 12,840 × 12,840
  4. Step 4: Simplify right side
    7,788x = 164,865,600
  5. Step 5: Solve for x
    x = 164,865,600/7,788
  6. Step 6: Final answer
    x = 21,169.18

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Why These Related Problems?

These problems maintain the same ratio (1.65) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.