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Finding the Fourth Proportional to 811.37, 1,215.78 and 378.02

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Solution

The fourth proportional to 811.37, 1,215.78 and 378.02 is: 566.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.37 : 1,215.78 = 378.02 : x
  2. Step 2: Convert to fraction form
    811.37/1,215.78 = 378.02/x
  3. Step 3: Cross multiply
    811.37x = 1,215.78 × 378.02
  4. Step 4: Simplify right side
    811.37x = 459,589.16
  5. Step 5: Solve for x
    x = 459,589.16/811.37
  6. Step 6: Final answer
    x = 566.44

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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.