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Finding the Fourth Proportional to 908.80, 1,362.60 and 421.21

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Solution

The fourth proportional to 908.80, 1,362.60 and 421.21 is: 631.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    908.80 : 1,362.60 = 421.21 : x
  2. Step 2: Convert to fraction form
    908.80/1,362.60 = 421.21/x
  3. Step 3: Cross multiply
    908.80x = 1,362.60 × 421.21
  4. Step 4: Simplify right side
    908.80x = 573,940.75
  5. Step 5: Solve for x
    x = 573,940.75/908.80
  6. Step 6: Final answer
    x = 631.54

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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.