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Finding the Third Proportional to 645 and 989

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Solution

The third proportional to 645 and 989 is: 1,516.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    645 : 989 = 989 : x
  2. Step 2: Convert to fraction form
    645/989 = 989/x
  3. Step 3: Cross multiply
    645x = 989 × 989
  4. Step 4: Simplify right side
    645x = 978,121
  5. Step 5: Solve for x
    x = 978,121/645
  6. Step 6: Final answer
    x = 1,516.47

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Why These Related Problems?

These problems maintain the same ratio (1.53) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.