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Finding the Third Proportional to 390.31 and 830.28

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Solution

The third proportional to 390.31 and 830.28 is: 1,766.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.31 : 830.28 = 830.28 : x
  2. Step 2: Convert to fraction form
    390.31/830.28 = 830.28/x
  3. Step 3: Cross multiply
    390.31x = 830.28 × 830.28
  4. Step 4: Simplify right side
    390.31x = 689,366.95
  5. Step 5: Solve for x
    x = 689,366.95/390.31
  6. Step 6: Final answer
    x = 1,766.19

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Why These Related Problems?

These problems maintain the same ratio (2.13) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.