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Finding the Fourth Proportional to 939.72, 1,409.48 and 419.74

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Solution

The fourth proportional to 939.72, 1,409.48 and 419.74 is: 629.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    939.72 : 1,409.48 = 419.74 : x
  2. Step 2: Convert to fraction form
    939.72/1,409.48 = 419.74/x
  3. Step 3: Cross multiply
    939.72x = 1,409.48 × 419.74
  4. Step 4: Simplify right side
    939.72x = 591,615.14
  5. Step 5: Solve for x
    x = 591,615.14/939.72
  6. Step 6: Final answer
    x = 629.57

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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.