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Finding the Third Proportional to 258 and 390.75

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Solution

The third proportional to 258 and 390.75 is: 591.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    258 : 390.75 = 390.75 : x
  2. Step 2: Convert to fraction form
    258/390.75 = 390.75/x
  3. Step 3: Cross multiply
    258x = 390.75 × 390.75
  4. Step 4: Simplify right side
    258x = 152,685.56
  5. Step 5: Solve for x
    x = 152,685.56/258
  6. Step 6: Final answer
    x = 591.80

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.