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Finding the Fourth Proportional to 678.63, 936.30 and 398.86

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Solution

The fourth proportional to 678.63, 936.30 and 398.86 is: 550.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.63 : 936.30 = 398.86 : x
  2. Step 2: Convert to fraction form
    678.63/936.30 = 398.86/x
  3. Step 3: Cross multiply
    678.63x = 936.30 × 398.86
  4. Step 4: Simplify right side
    678.63x = 373,452.62
  5. Step 5: Solve for x
    x = 373,452.62/678.63
  6. Step 6: Final answer
    x = 550.30

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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.