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Finding the Fourth Proportional to 678.58, 1,018.25 and 419.21

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Solution

The fourth proportional to 678.58, 1,018.25 and 419.21 is: 629.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.58 : 1,018.25 = 419.21 : x
  2. Step 2: Convert to fraction form
    678.58/1,018.25 = 419.21/x
  3. Step 3: Cross multiply
    678.58x = 1,018.25 × 419.21
  4. Step 4: Simplify right side
    678.58x = 426,864.18
  5. Step 5: Solve for x
    x = 426,864.18/678.58
  6. Step 6: Final answer
    x = 629.06

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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.