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Finding the Fourth Proportional to 678.98, 936.86 and 399.24

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Solution

The fourth proportional to 678.98, 936.86 and 399.24 is: 550.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.98 : 936.86 = 399.24 : x
  2. Step 2: Convert to fraction form
    678.98/936.86 = 399.24/x
  3. Step 3: Cross multiply
    678.98x = 936.86 × 399.24
  4. Step 4: Simplify right side
    678.98x = 374,029.99
  5. Step 5: Solve for x
    x = 374,029.99/678.98
  6. Step 6: Final answer
    x = 550.87

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.