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Finding the Fourth Proportional to 869.20, 1,190.90 and 857.05

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Solution

The fourth proportional to 869.20, 1,190.90 and 857.05 is: 1,174.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    869.20 : 1,190.90 = 857.05 : x
  2. Step 2: Convert to fraction form
    869.20/1,190.90 = 857.05/x
  3. Step 3: Cross multiply
    869.20x = 1,190.90 × 857.05
  4. Step 4: Simplify right side
    869.20x = 1,020,660.01
  5. Step 5: Solve for x
    x = 1,020,660.01/869.20
  6. Step 6: Final answer
    x = 1,174.26

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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.