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Finding the Third Proportional to 8,439 and 12,988

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Solution

The third proportional to 8,439 and 12,988 is: 19,989.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    8,439 : 12,988 = 12,988 : x
  2. Step 2: Convert to fraction form
    8,439/12,988 = 12,988/x
  3. Step 3: Cross multiply
    8,439x = 12,988 × 12,988
  4. Step 4: Simplify right side
    8,439x = 168,688,144
  5. Step 5: Solve for x
    x = 168,688,144/8,439
  6. Step 6: Final answer
    x = 19,989.12

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Why These Related Problems?

These problems maintain the same ratio (1.54) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.