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Finding the Fourth Proportional to 679.21, 1,019.44 and 419.72

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Solution

The fourth proportional to 679.21, 1,019.44 and 419.72 is: 629.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    679.21 : 1,019.44 = 419.72 : x
  2. Step 2: Convert to fraction form
    679.21/1,019.44 = 419.72/x
  3. Step 3: Cross multiply
    679.21x = 1,019.44 × 419.72
  4. Step 4: Simplify right side
    679.21x = 427,872.42
  5. Step 5: Solve for x
    x = 427,872.42/679.21
  6. Step 6: Final answer
    x = 629.96

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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.