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Finding the Third Proportional to 420.81 and 645.94

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Solution

The third proportional to 420.81 and 645.94 is: 991.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.81 : 645.94 = 645.94 : x
  2. Step 2: Convert to fraction form
    420.81/645.94 = 645.94/x
  3. Step 3: Cross multiply
    420.81x = 645.94 × 645.94
  4. Step 4: Simplify right side
    420.81x = 417,235.25
  5. Step 5: Solve for x
    x = 417,235.25/420.81
  6. Step 6: Final answer
    x = 991.50

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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.