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Finding the Fourth Proportional to 811.55, 1,120.30 and 517.21

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Solution

The fourth proportional to 811.55, 1,120.30 and 517.21 is: 713.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.55 : 1,120.30 = 517.21 : x
  2. Step 2: Convert to fraction form
    811.55/1,120.30 = 517.21/x
  3. Step 3: Cross multiply
    811.55x = 1,120.30 × 517.21
  4. Step 4: Simplify right side
    811.55x = 579,426.27
  5. Step 5: Solve for x
    x = 579,426.27/811.55
  6. Step 6: Final answer
    x = 713.98

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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.