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Finding the Third Proportional to 258 and 399.50

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Solution

The third proportional to 258 and 399.50 is: 618.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    258 : 399.50 = 399.50 : x
  2. Step 2: Convert to fraction form
    258/399.50 = 399.50/x
  3. Step 3: Cross multiply
    258x = 399.50 × 399.50
  4. Step 4: Simplify right side
    258x = 159,600.25
  5. Step 5: Solve for x
    x = 159,600.25/258
  6. Step 6: Final answer
    x = 618.61

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These problems maintain the same ratio (1.55) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.