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Finding the Fourth Proportional to 1,091, 1,505.78 and 857.72

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Solution

The fourth proportional to 1,091, 1,505.78 and 857.72 is: 1,183.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,091 : 1,505.78 = 857.72 : x
  2. Step 2: Convert to fraction form
    1,091/1,505.78 = 857.72/x
  3. Step 3: Cross multiply
    1,091x = 1,505.78 × 857.72
  4. Step 4: Simplify right side
    1,091x = 1,291,537.62
  5. Step 5: Solve for x
    x = 1,291,537.62/1,091
  6. Step 6: Final answer
    x = 1,183.81

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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.