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Finding the Third Proportional to 390.75 and 622.50

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Solution

The third proportional to 390.75 and 622.50 is: 991.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.75 : 622.50 = 622.50 : x
  2. Step 2: Convert to fraction form
    390.75/622.50 = 622.50/x
  3. Step 3: Cross multiply
    390.75x = 622.50 × 622.50
  4. Step 4: Simplify right side
    390.75x = 387,506.25
  5. Step 5: Solve for x
    x = 387,506.25/390.75
  6. Step 6: Final answer
    x = 991.70

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Why These Related Problems?

These problems maintain the same ratio (1.59) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.