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Finding the Fourth Proportional to 1,398, 2,096.64 and 821.28

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Solution

The fourth proportional to 1,398, 2,096.64 and 821.28 is: 1,231.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,398 : 2,096.64 = 821.28 : x
  2. Step 2: Convert to fraction form
    1,398/2,096.64 = 821.28/x
  3. Step 3: Cross multiply
    1,398x = 2,096.64 × 821.28
  4. Step 4: Simplify right side
    1,398x = 1,721,928.50
  5. Step 5: Solve for x
    x = 1,721,928.50/1,398
  6. Step 6: Final answer
    x = 1,231.71

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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.