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Finding the Fourth Proportional to 919.81, 1,378.81 and 838.81

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Solution

The fourth proportional to 919.81, 1,378.81 and 838.81 is: 1,257.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    919.81 : 1,378.81 = 838.81 : x
  2. Step 2: Convert to fraction form
    919.81/1,378.81 = 838.81/x
  3. Step 3: Cross multiply
    919.81x = 1,378.81 × 838.81
  4. Step 4: Simplify right side
    919.81x = 1,156,559.62
  5. Step 5: Solve for x
    x = 1,156,559.62/919.81
  6. Step 6: Final answer
    x = 1,257.39

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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.