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Finding the Fourth Proportional to 811.43, 1,120.19 and 620.87

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Solution

The fourth proportional to 811.43, 1,120.19 and 620.87 is: 857.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.43 : 1,120.19 = 620.87 : x
  2. Step 2: Convert to fraction form
    811.43/1,120.19 = 620.87/x
  3. Step 3: Cross multiply
    811.43x = 1,120.19 × 620.87
  4. Step 4: Simplify right side
    811.43x = 695,492.06
  5. Step 5: Solve for x
    x = 695,492.06/811.43
  6. Step 6: Final answer
    x = 857.12

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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.