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Finding the Third Proportional to 40 and 78

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Solution

The third proportional to 40 and 78 is: 152.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    40 : 78 = 78 : x
  2. Step 2: Convert to fraction form
    40/78 = 78/x
  3. Step 3: Cross multiply
    40x = 78 × 78
  4. Step 4: Simplify right side
    40x = 6,084
  5. Step 5: Solve for x
    x = 6,084/40
  6. Step 6: Final answer
    x = 152.10

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Why These Related Problems?

These problems maintain the same ratio (1.95) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.