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Finding the Fourth Proportional to 678.44, 936.34 and 398.79

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Solution

The fourth proportional to 678.44, 936.34 and 398.79 is: 550.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.44 : 936.34 = 398.79 : x
  2. Step 2: Convert to fraction form
    678.44/936.34 = 398.79/x
  3. Step 3: Cross multiply
    678.44x = 936.34 × 398.79
  4. Step 4: Simplify right side
    678.44x = 373,403.03
  5. Step 5: Solve for x
    x = 373,403.03/678.44
  6. Step 6: Final answer
    x = 550.38

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Double scale
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1.5x scale

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.