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Finding the Third Proportional to 420.75 and 561.25

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Solution

The third proportional to 420.75 and 561.25 is: 748.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.75 : 561.25 = 561.25 : x
  2. Step 2: Convert to fraction form
    420.75/561.25 = 561.25/x
  3. Step 3: Cross multiply
    420.75x = 561.25 × 561.25
  4. Step 4: Simplify right side
    420.75x = 315,001.56
  5. Step 5: Solve for x
    x = 315,001.56/420.75
  6. Step 6: Final answer
    x = 748.67

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Why These Related Problems?

These problems maintain the same ratio (1.33) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.