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Finding the Third Proportional to 420 and 891

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Solution

The third proportional to 420 and 891 is: 1,890.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    420 : 891 = 891 : x
  2. Step 2: Convert to fraction form
    420/891 = 891/x
  3. Step 3: Cross multiply
    420x = 891 × 891
  4. Step 4: Simplify right side
    420x = 793,881
  5. Step 5: Solve for x
    x = 793,881/420
  6. Step 6: Final answer
    x = 1,890.19

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Why These Related Problems?

These problems maintain the same ratio (2.12) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.