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Finding the Fourth Proportional to 879.42, 1,212.79 and 809.63

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Solution

The fourth proportional to 879.42, 1,212.79 and 809.63 is: 1,116.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    879.42 : 1,212.79 = 809.63 : x
  2. Step 2: Convert to fraction form
    879.42/1,212.79 = 809.63/x
  3. Step 3: Cross multiply
    879.42x = 1,212.79 × 809.63
  4. Step 4: Simplify right side
    879.42x = 981,911.17
  5. Step 5: Solve for x
    x = 981,911.17/879.42
  6. Step 6: Final answer
    x = 1,116.54

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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.