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Finding the Fourth Proportional to 854.20, 1,278.10 and 777.40

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Solution

The fourth proportional to 854.20, 1,278.10 and 777.40 is: 1,163.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    854.20 : 1,278.10 = 777.40 : x
  2. Step 2: Convert to fraction form
    854.20/1,278.10 = 777.40/x
  3. Step 3: Cross multiply
    854.20x = 1,278.10 × 777.40
  4. Step 4: Simplify right side
    854.20x = 993,594.94
  5. Step 5: Solve for x
    x = 993,594.94/854.20
  6. Step 6: Final answer
    x = 1,163.19

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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.