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Finding the Fourth Proportional to 681.94, 1,021.20 and 438.49

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Solution

The fourth proportional to 681.94, 1,021.20 and 438.49 is: 656.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    681.94 : 1,021.20 = 438.49 : x
  2. Step 2: Convert to fraction form
    681.94/1,021.20 = 438.49/x
  3. Step 3: Cross multiply
    681.94x = 1,021.20 × 438.49
  4. Step 4: Simplify right side
    681.94x = 447,785.99
  5. Step 5: Solve for x
    x = 447,785.99/681.94
  6. Step 6: Final answer
    x = 656.64

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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.