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Finding the Third Proportional to 390 and 521

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Solution

The third proportional to 390 and 521 is: 696.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    390 : 521 = 521 : x
  2. Step 2: Convert to fraction form
    390/521 = 521/x
  3. Step 3: Cross multiply
    390x = 521 × 521
  4. Step 4: Simplify right side
    390x = 271,441
  5. Step 5: Solve for x
    x = 271,441/390
  6. Step 6: Final answer
    x = 696.00

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Why These Related Problems?

These problems maintain the same ratio (1.34) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.