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Finding the Fourth Proportional to 856.68, 1,286 and 685.44

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Solution

The fourth proportional to 856.68, 1,286 and 685.44 is: 1,028.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    856.68 : 1,286 = 685.44 : x
  2. Step 2: Convert to fraction form
    856.68/1,286 = 685.44/x
  3. Step 3: Cross multiply
    856.68x = 1,286 × 685.44
  4. Step 4: Simplify right side
    856.68x = 881,475.84
  5. Step 5: Solve for x
    x = 881,475.84/856.68
  6. Step 6: Final answer
    x = 1,028.94

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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.