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Finding the Fourth Proportional to 1,679.40, 2,516.10 and 811.80

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Solution

The fourth proportional to 1,679.40, 2,516.10 and 811.80 is: 1,216.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,679.40 : 2,516.10 = 811.80 : x
  2. Step 2: Convert to fraction form
    1,679.40/2,516.10 = 811.80/x
  3. Step 3: Cross multiply
    1,679.40x = 2,516.10 × 811.80
  4. Step 4: Simplify right side
    1,679.40x = 2,042,569.98
  5. Step 5: Solve for x
    x = 2,042,569.98/1,679.40
  6. Step 6: Final answer
    x = 1,216.25

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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.