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Finding the Fourth Proportional to 821.80, 1,134.18 and 778.60

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Solution

The fourth proportional to 821.80, 1,134.18 and 778.60 is: 1,074.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.80 : 1,134.18 = 778.60 : x
  2. Step 2: Convert to fraction form
    821.80/1,134.18 = 778.60/x
  3. Step 3: Cross multiply
    821.80x = 1,134.18 × 778.60
  4. Step 4: Simplify right side
    821.80x = 883,072.55
  5. Step 5: Solve for x
    x = 883,072.55/821.80
  6. Step 6: Final answer
    x = 1,074.56

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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.