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Finding the Fourth Proportional to 1,442.80, 1,990.96 and 821.80

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Solution

The fourth proportional to 1,442.80, 1,990.96 and 821.80 is: 1,134.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,442.80 : 1,990.96 = 821.80 : x
  2. Step 2: Convert to fraction form
    1,442.80/1,990.96 = 821.80/x
  3. Step 3: Cross multiply
    1,442.80x = 1,990.96 × 821.80
  4. Step 4: Simplify right side
    1,442.80x = 1,636,170.93
  5. Step 5: Solve for x
    x = 1,636,170.93/1,442.80
  6. Step 6: Final answer
    x = 1,134.02

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.