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Finding the Fourth Proportional to 678.64, 1,018.15 and 191.69

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Solution

The fourth proportional to 678.64, 1,018.15 and 191.69 is: 287.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.64 : 1,018.15 = 191.69 : x
  2. Step 2: Convert to fraction form
    678.64/1,018.15 = 191.69/x
  3. Step 3: Cross multiply
    678.64x = 1,018.15 × 191.69
  4. Step 4: Simplify right side
    678.64x = 195,169.17
  5. Step 5: Solve for x
    x = 195,169.17/678.64
  6. Step 6: Final answer
    x = 287.59

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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.