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Finding the Fourth Proportional to 321.99, 443.21 and 305.60

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Solution

The fourth proportional to 321.99, 443.21 and 305.60 is: 420.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    321.99 : 443.21 = 305.60 : x
  2. Step 2: Convert to fraction form
    321.99/443.21 = 305.60/x
  3. Step 3: Cross multiply
    321.99x = 443.21 × 305.60
  4. Step 4: Simplify right side
    321.99x = 135,441.23
  5. Step 5: Solve for x
    x = 135,441.23/321.99
  6. Step 6: Final answer
    x = 420.64

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.