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Finding the Third Proportional to 312.56 and 678.56

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Solution

The third proportional to 312.56 and 678.56 is: 1,473.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    312.56 : 678.56 = 678.56 : x
  2. Step 2: Convert to fraction form
    312.56/678.56 = 678.56/x
  3. Step 3: Cross multiply
    312.56x = 678.56 × 678.56
  4. Step 4: Simplify right side
    312.56x = 460,447.07
  5. Step 5: Solve for x
    x = 460,447.07/312.56
  6. Step 6: Final answer
    x = 1,473.14

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Why These Related Problems?

These problems maintain the same ratio (2.17) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.