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Finding the Fourth Proportional to 810.92, 1,214.40 and 378.20

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Solution

The fourth proportional to 810.92, 1,214.40 and 378.20 is: 566.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    810.92 : 1,214.40 = 378.20 : x
  2. Step 2: Convert to fraction form
    810.92/1,214.40 = 378.20/x
  3. Step 3: Cross multiply
    810.92x = 1,214.40 × 378.20
  4. Step 4: Simplify right side
    810.92x = 459,286.08
  5. Step 5: Solve for x
    x = 459,286.08/810.92
  6. Step 6: Final answer
    x = 566.38

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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.