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Finding the Fourth Proportional to 811.52, 1,214 and 613.92

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Solution

The fourth proportional to 811.52, 1,214 and 613.92 is: 918.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.52 : 1,214 = 613.92 : x
  2. Step 2: Convert to fraction form
    811.52/1,214 = 613.92/x
  3. Step 3: Cross multiply
    811.52x = 1,214 × 613.92
  4. Step 4: Simplify right side
    811.52x = 745,298.88
  5. Step 5: Solve for x
    x = 745,298.88/811.52
  6. Step 6: Final answer
    x = 918.40

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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.