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Finding the Third Proportional to 156 and 421.50

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Solution

The third proportional to 156 and 421.50 is: 1,138.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    156 : 421.50 = 421.50 : x
  2. Step 2: Convert to fraction form
    156/421.50 = 421.50/x
  3. Step 3: Cross multiply
    156x = 421.50 × 421.50
  4. Step 4: Simplify right side
    156x = 177,662.25
  5. Step 5: Solve for x
    x = 177,662.25/156
  6. Step 6: Final answer
    x = 1,138.86

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Why These Related Problems?

These problems maintain the same ratio (2.70) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.