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Finding the Third Proportional to 420.50 and 620.75

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Solution

The third proportional to 420.50 and 620.75 is: 916.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.50 : 620.75 = 620.75 : x
  2. Step 2: Convert to fraction form
    420.50/620.75 = 620.75/x
  3. Step 3: Cross multiply
    420.50x = 620.75 × 620.75
  4. Step 4: Simplify right side
    420.50x = 385,330.56
  5. Step 5: Solve for x
    x = 385,330.56/420.50
  6. Step 6: Final answer
    x = 916.36

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Why These Related Problems?

These problems maintain the same ratio (1.48) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.