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Finding the Third Proportional to 218.58 and 386.07

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Solution

The third proportional to 218.58 and 386.07 is: 681.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    218.58 : 386.07 = 386.07 : x
  2. Step 2: Convert to fraction form
    218.58/386.07 = 386.07/x
  3. Step 3: Cross multiply
    218.58x = 386.07 × 386.07
  4. Step 4: Simplify right side
    218.58x = 149,048.78
  5. Step 5: Solve for x
    x = 149,048.78/218.58
  6. Step 6: Final answer
    x = 681.88

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Why These Related Problems?

These problems maintain the same ratio (1.77) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.