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Finding the Fourth Proportional to 855.55, 1,280.21 and 790.21

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Solution

The fourth proportional to 855.55, 1,280.21 and 790.21 is: 1,182.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    855.55 : 1,280.21 = 790.21 : x
  2. Step 2: Convert to fraction form
    855.55/1,280.21 = 790.21/x
  3. Step 3: Cross multiply
    855.55x = 1,280.21 × 790.21
  4. Step 4: Simplify right side
    855.55x = 1,011,627.59
  5. Step 5: Solve for x
    x = 1,011,627.59/855.55
  6. Step 6: Final answer
    x = 1,182.43

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.