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Finding the Fourth Proportional to 811.38, 1,215 and 696.58

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Solution

The fourth proportional to 811.38, 1,215 and 696.58 is: 1,043.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.38 : 1,215 = 696.58 : x
  2. Step 2: Convert to fraction form
    811.38/1,215 = 696.58/x
  3. Step 3: Cross multiply
    811.38x = 1,215 × 696.58
  4. Step 4: Simplify right side
    811.38x = 846,344.70
  5. Step 5: Solve for x
    x = 846,344.70/811.38
  6. Step 6: Final answer
    x = 1,043.09

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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.