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Finding the Fourth Proportional to 678.56, 1,017.87 and 191.64

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Solution

The fourth proportional to 678.56, 1,017.87 and 191.64 is: 287.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.56 : 1,017.87 = 191.64 : x
  2. Step 2: Convert to fraction form
    678.56/1,017.87 = 191.64/x
  3. Step 3: Cross multiply
    678.56x = 1,017.87 × 191.64
  4. Step 4: Simplify right side
    678.56x = 195,063.65
  5. Step 5: Solve for x
    x = 195,063.65/678.56
  6. Step 6: Final answer
    x = 287.47

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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.