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Finding the Third Proportional to 311 and 420.50

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Solution

The third proportional to 311 and 420.50 is: 568.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    311 : 420.50 = 420.50 : x
  2. Step 2: Convert to fraction form
    311/420.50 = 420.50/x
  3. Step 3: Cross multiply
    311x = 420.50 × 420.50
  4. Step 4: Simplify right side
    311x = 176,820.25
  5. Step 5: Solve for x
    x = 176,820.25/311
  6. Step 6: Final answer
    x = 568.55

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Why These Related Problems?

These problems maintain the same ratio (1.35) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.