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Finding the Third Proportional to 217.90 and 312.19

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Solution

The third proportional to 217.90 and 312.19 is: 447.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    217.90 : 312.19 = 312.19 : x
  2. Step 2: Convert to fraction form
    217.90/312.19 = 312.19/x
  3. Step 3: Cross multiply
    217.90x = 312.19 × 312.19
  4. Step 4: Simplify right side
    217.90x = 97,461.04
  5. Step 5: Solve for x
    x = 97,461.04/217.90
  6. Step 6: Final answer
    x = 447.28

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Why These Related Problems?

These problems maintain the same ratio (1.43) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.