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Finding the Fourth Proportional to 811.20, 1,119.36 and 479.60

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Solution

The fourth proportional to 811.20, 1,119.36 and 479.60 is: 661.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.20 : 1,119.36 = 479.60 : x
  2. Step 2: Convert to fraction form
    811.20/1,119.36 = 479.60/x
  3. Step 3: Cross multiply
    811.20x = 1,119.36 × 479.60
  4. Step 4: Simplify right side
    811.20x = 536,845.06
  5. Step 5: Solve for x
    x = 536,845.06/811.20
  6. Step 6: Final answer
    x = 661.79

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.