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Finding the Third Proportional to 390 and 520.50

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Solution

The third proportional to 390 and 520.50 is: 694.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    390 : 520.50 = 520.50 : x
  2. Step 2: Convert to fraction form
    390/520.50 = 520.50/x
  3. Step 3: Cross multiply
    390x = 520.50 × 520.50
  4. Step 4: Simplify right side
    390x = 270,920.25
  5. Step 5: Solve for x
    x = 270,920.25/390
  6. Step 6: Final answer
    x = 694.67

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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.