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Finding the Fourth Proportional to 842.09, 1,161.99 and 621.15

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Solution

The fourth proportional to 842.09, 1,161.99 and 621.15 is: 857.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    842.09 : 1,161.99 = 621.15 : x
  2. Step 2: Convert to fraction form
    842.09/1,161.99 = 621.15/x
  3. Step 3: Cross multiply
    842.09x = 1,161.99 × 621.15
  4. Step 4: Simplify right side
    842.09x = 721,770.09
  5. Step 5: Solve for x
    x = 721,770.09/842.09
  6. Step 6: Final answer
    x = 857.12

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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.