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Finding the Fourth Proportional to 857.72, 1,183.80 and 661.70

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Solution

The fourth proportional to 857.72, 1,183.80 and 661.70 is: 913.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    857.72 : 1,183.80 = 661.70 : x
  2. Step 2: Convert to fraction form
    857.72/1,183.80 = 661.70/x
  3. Step 3: Cross multiply
    857.72x = 1,183.80 × 661.70
  4. Step 4: Simplify right side
    857.72x = 783,314.54
  5. Step 5: Solve for x
    x = 783,314.54/857.72
  6. Step 6: Final answer
    x = 913.26

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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.