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Finding the Fourth Proportional to 817.64, 1,128.48 and 620.80

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Solution

The fourth proportional to 817.64, 1,128.48 and 620.80 is: 856.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    817.64 : 1,128.48 = 620.80 : x
  2. Step 2: Convert to fraction form
    817.64/1,128.48 = 620.80/x
  3. Step 3: Cross multiply
    817.64x = 1,128.48 × 620.80
  4. Step 4: Simplify right side
    817.64x = 700,560.38
  5. Step 5: Solve for x
    x = 700,560.38/817.64
  6. Step 6: Final answer
    x = 856.81

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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.