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Finding the Third Proportional to 72 and 78.25

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Solution

The third proportional to 72 and 78.25 is: 85.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    72 : 78.25 = 78.25 : x
  2. Step 2: Convert to fraction form
    72/78.25 = 78.25/x
  3. Step 3: Cross multiply
    72x = 78.25 × 78.25
  4. Step 4: Simplify right side
    72x = 6,123.06
  5. Step 5: Solve for x
    x = 6,123.06/72
  6. Step 6: Final answer
    x = 85.04

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Why These Related Problems?

These problems maintain the same ratio (1.09) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.