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Finding the Fourth Proportional to 1,280.75, 1,921.11 and 847.80

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Solution

The fourth proportional to 1,280.75, 1,921.11 and 847.80 is: 1,271.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,280.75 : 1,921.11 = 847.80 : x
  2. Step 2: Convert to fraction form
    1,280.75/1,921.11 = 847.80/x
  3. Step 3: Cross multiply
    1,280.75x = 1,921.11 × 847.80
  4. Step 4: Simplify right side
    1,280.75x = 1,628,717.06
  5. Step 5: Solve for x
    x = 1,628,717.06/1,280.75
  6. Step 6: Final answer
    x = 1,271.69

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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.