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Finding the Fourth Proportional to 919.82, 1,380 and 487.28

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Solution

The fourth proportional to 919.82, 1,380 and 487.28 is: 731.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    919.82 : 1,380 = 487.28 : x
  2. Step 2: Convert to fraction form
    919.82/1,380 = 487.28/x
  3. Step 3: Cross multiply
    919.82x = 1,380 × 487.28
  4. Step 4: Simplify right side
    919.82x = 672,446.40
  5. Step 5: Solve for x
    x = 672,446.40/919.82
  6. Step 6: Final answer
    x = 731.06

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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.