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Finding the Fourth Proportional to 905.68, 1,355.82 and 811.80

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Solution

The fourth proportional to 905.68, 1,355.82 and 811.80 is: 1,215.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    905.68 : 1,355.82 = 811.80 : x
  2. Step 2: Convert to fraction form
    905.68/1,355.82 = 811.80/x
  3. Step 3: Cross multiply
    905.68x = 1,355.82 × 811.80
  4. Step 4: Simplify right side
    905.68x = 1,100,654.68
  5. Step 5: Solve for x
    x = 1,100,654.68/905.68
  6. Step 6: Final answer
    x = 1,215.28

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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.