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Finding the Fourth Proportional to 905.80, 1,358.72 and 419.28

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Solution

The fourth proportional to 905.80, 1,358.72 and 419.28 is: 628.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    905.80 : 1,358.72 = 419.28 : x
  2. Step 2: Convert to fraction form
    905.80/1,358.72 = 419.28/x
  3. Step 3: Cross multiply
    905.80x = 1,358.72 × 419.28
  4. Step 4: Simplify right side
    905.80x = 569,684.12
  5. Step 5: Solve for x
    x = 569,684.12/905.80
  6. Step 6: Final answer
    x = 628.93

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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.