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Finding the Third Proportional to 120 and 215

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Solution

The third proportional to 120 and 215 is: 385.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    120 : 215 = 215 : x
  2. Step 2: Convert to fraction form
    120/215 = 215/x
  3. Step 3: Cross multiply
    120x = 215 × 215
  4. Step 4: Simplify right side
    120x = 46,225
  5. Step 5: Solve for x
    x = 46,225/120
  6. Step 6: Final answer
    x = 385.21

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Why These Related Problems?

These problems maintain the same ratio (1.79) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.