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Finding the Fourth Proportional to 811.80, 1,120.38 and 513.48

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Solution

The fourth proportional to 811.80, 1,120.38 and 513.48 is: 708.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.80 : 1,120.38 = 513.48 : x
  2. Step 2: Convert to fraction form
    811.80/1,120.38 = 513.48/x
  3. Step 3: Cross multiply
    811.80x = 1,120.38 × 513.48
  4. Step 4: Simplify right side
    811.80x = 575,292.72
  5. Step 5: Solve for x
    x = 575,292.72/811.80
  6. Step 6: Final answer
    x = 708.66

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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.