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Finding the Fourth Proportional to 919.31, 1,378.32 and 399.04

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Solution

The fourth proportional to 919.31, 1,378.32 and 399.04 is: 598.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    919.31 : 1,378.32 = 399.04 : x
  2. Step 2: Convert to fraction form
    919.31/1,378.32 = 399.04/x
  3. Step 3: Cross multiply
    919.31x = 1,378.32 × 399.04
  4. Step 4: Simplify right side
    919.31x = 550,008.70
  5. Step 5: Solve for x
    x = 550,008.70/919.31
  6. Step 6: Final answer
    x = 598.28

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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.