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Finding the Fourth Proportional to 817.76, 1,128.96 and 621.80

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Solution

The fourth proportional to 817.76, 1,128.96 and 621.80 is: 858.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    817.76 : 1,128.96 = 621.80 : x
  2. Step 2: Convert to fraction form
    817.76/1,128.96 = 621.80/x
  3. Step 3: Cross multiply
    817.76x = 1,128.96 × 621.80
  4. Step 4: Simplify right side
    817.76x = 701,987.33
  5. Step 5: Solve for x
    x = 701,987.33/817.76
  6. Step 6: Final answer
    x = 858.43

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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.