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Finding the Fourth Proportional to 681.13, 1,021.38 and 218.81

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Solution

The fourth proportional to 681.13, 1,021.38 and 218.81 is: 328.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    681.13 : 1,021.38 = 218.81 : x
  2. Step 2: Convert to fraction form
    681.13/1,021.38 = 218.81/x
  3. Step 3: Cross multiply
    681.13x = 1,021.38 × 218.81
  4. Step 4: Simplify right side
    681.13x = 223,488.16
  5. Step 5: Solve for x
    x = 223,488.16/681.13
  6. Step 6: Final answer
    x = 328.11

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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.