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Finding the Third Proportional to 390 and 457

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Solution

The third proportional to 390 and 457 is: 535.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    390 : 457 = 457 : x
  2. Step 2: Convert to fraction form
    390/457 = 457/x
  3. Step 3: Cross multiply
    390x = 457 × 457
  4. Step 4: Simplify right side
    390x = 208,849
  5. Step 5: Solve for x
    x = 208,849/390
  6. Step 6: Final answer
    x = 535.51

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Why These Related Problems?

These problems maintain the same ratio (1.17) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.