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Finding the Third Proportional to 261 and 318.75

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Solution

The third proportional to 261 and 318.75 is: 389.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    261 : 318.75 = 318.75 : x
  2. Step 2: Convert to fraction form
    261/318.75 = 318.75/x
  3. Step 3: Cross multiply
    261x = 318.75 × 318.75
  4. Step 4: Simplify right side
    261x = 101,601.56
  5. Step 5: Solve for x
    x = 101,601.56/261
  6. Step 6: Final answer
    x = 389.28

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Why These Related Problems?

These problems maintain the same ratio (1.22) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.