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Finding the Third Proportional to 390.50 and 619.75

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Solution

The third proportional to 390.50 and 619.75 is: 983.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.50 : 619.75 = 619.75 : x
  2. Step 2: Convert to fraction form
    390.50/619.75 = 619.75/x
  3. Step 3: Cross multiply
    390.50x = 619.75 × 619.75
  4. Step 4: Simplify right side
    390.50x = 384,090.06
  5. Step 5: Solve for x
    x = 384,090.06/390.50
  6. Step 6: Final answer
    x = 983.59

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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.