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Finding the Third Proportional to 312.75 and 686.25

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Solution

The third proportional to 312.75 and 686.25 is: 1,505.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    312.75 : 686.25 = 686.25 : x
  2. Step 2: Convert to fraction form
    312.75/686.25 = 686.25/x
  3. Step 3: Cross multiply
    312.75x = 686.25 × 686.25
  4. Step 4: Simplify right side
    312.75x = 470,939.06
  5. Step 5: Solve for x
    x = 470,939.06/312.75
  6. Step 6: Final answer
    x = 1,505.80

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Why These Related Problems?

These problems maintain the same ratio (2.19) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.