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Finding the Fourth Proportional to 905.78, 1,357.31 and 808.28

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Solution

The fourth proportional to 905.78, 1,357.31 and 808.28 is: 1,211.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    905.78 : 1,357.31 = 808.28 : x
  2. Step 2: Convert to fraction form
    905.78/1,357.31 = 808.28/x
  3. Step 3: Cross multiply
    905.78x = 1,357.31 × 808.28
  4. Step 4: Simplify right side
    905.78x = 1,097,082.30
  5. Step 5: Solve for x
    x = 1,097,082.30/905.78
  6. Step 6: Final answer
    x = 1,211.20

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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.