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Finding the Fourth Proportional to 680.69, 1,020.89 and 218.51

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Solution

The fourth proportional to 680.69, 1,020.89 and 218.51 is: 327.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.69 : 1,020.89 = 218.51 : x
  2. Step 2: Convert to fraction form
    680.69/1,020.89 = 218.51/x
  3. Step 3: Cross multiply
    680.69x = 1,020.89 × 218.51
  4. Step 4: Simplify right side
    680.69x = 223,068.48
  5. Step 5: Solve for x
    x = 223,068.48/680.69
  6. Step 6: Final answer
    x = 327.71

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.