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Finding the Fourth Proportional to 857.56, 1,286.72 and 784.64

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Solution

The fourth proportional to 857.56, 1,286.72 and 784.64 is: 1,177.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    857.56 : 1,286.72 = 784.64 : x
  2. Step 2: Convert to fraction form
    857.56/1,286.72 = 784.64/x
  3. Step 3: Cross multiply
    857.56x = 1,286.72 × 784.64
  4. Step 4: Simplify right side
    857.56x = 1,009,611.98
  5. Step 5: Solve for x
    x = 1,009,611.98/857.56
  6. Step 6: Final answer
    x = 1,177.31

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.