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Finding the Third Proportional to 315.75 and 690.56

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Solution

The third proportional to 315.75 and 690.56 is: 1,510.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    315.75 : 690.56 = 690.56 : x
  2. Step 2: Convert to fraction form
    315.75/690.56 = 690.56/x
  3. Step 3: Cross multiply
    315.75x = 690.56 × 690.56
  4. Step 4: Simplify right side
    315.75x = 476,876.57
  5. Step 5: Solve for x
    x = 476,876.57/315.75
  6. Step 6: Final answer
    x = 1,510.30

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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.