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Finding the Third Proportional to 42 and 78.75

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Solution

The third proportional to 42 and 78.75 is: 147.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    42 : 78.75 = 78.75 : x
  2. Step 2: Convert to fraction form
    42/78.75 = 78.75/x
  3. Step 3: Cross multiply
    42x = 78.75 × 78.75
  4. Step 4: Simplify right side
    42x = 6,201.56
  5. Step 5: Solve for x
    x = 6,201.56/42
  6. Step 6: Final answer
    x = 147.66

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Why These Related Problems?

These problems maintain the same ratio (1.88) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.