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Finding the Fourth Proportional to 811.08, 1,214.39 and 615.50

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Solution

The fourth proportional to 811.08, 1,214.39 and 615.50 is: 921.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.08 : 1,214.39 = 615.50 : x
  2. Step 2: Convert to fraction form
    811.08/1,214.39 = 615.50/x
  3. Step 3: Cross multiply
    811.08x = 1,214.39 × 615.50
  4. Step 4: Simplify right side
    811.08x = 747,453.97
  5. Step 5: Solve for x
    x = 747,453.97/811.08
  6. Step 6: Final answer
    x = 921.56

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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.