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Finding the Fourth Proportional to 998.40, 1,371.60 and 823.20

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Solution

The fourth proportional to 998.40, 1,371.60 and 823.20 is: 1,130.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    998.40 : 1,371.60 = 823.20 : x
  2. Step 2: Convert to fraction form
    998.40/1,371.60 = 823.20/x
  3. Step 3: Cross multiply
    998.40x = 1,371.60 × 823.20
  4. Step 4: Simplify right side
    998.40x = 1,129,101.12
  5. Step 5: Solve for x
    x = 1,129,101.12/998.40
  6. Step 6: Final answer
    x = 1,130.91

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.