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Finding the Third Proportional to 256.61 and 390.13

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Solution

The third proportional to 256.61 and 390.13 is: 593.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    256.61 : 390.13 = 390.13 : x
  2. Step 2: Convert to fraction form
    256.61/390.13 = 390.13/x
  3. Step 3: Cross multiply
    256.61x = 390.13 × 390.13
  4. Step 4: Simplify right side
    256.61x = 152,200.56
  5. Step 5: Solve for x
    x = 152,200.56/256.61
  6. Step 6: Final answer
    x = 593.13

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Why These Related Problems?

These problems maintain the same ratio (1.52) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.