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Finding the Fourth Proportional to 905.40, 1,355.40 and 808.20

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Solution

The fourth proportional to 905.40, 1,355.40 and 808.20 is: 1,209.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    905.40 : 1,355.40 = 808.20 : x
  2. Step 2: Convert to fraction form
    905.40/1,355.40 = 808.20/x
  3. Step 3: Cross multiply
    905.40x = 1,355.40 × 808.20
  4. Step 4: Simplify right side
    905.40x = 1,095,434.28
  5. Step 5: Solve for x
    x = 1,095,434.28/905.40
  6. Step 6: Final answer
    x = 1,209.89

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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.