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Finding the Fourth Proportional to 398.09, 549.98 and 305.21

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Solution

The fourth proportional to 398.09, 549.98 and 305.21 is: 421.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    398.09 : 549.98 = 305.21 : x
  2. Step 2: Convert to fraction form
    398.09/549.98 = 305.21/x
  3. Step 3: Cross multiply
    398.09x = 549.98 × 305.21
  4. Step 4: Simplify right side
    398.09x = 167,859.40
  5. Step 5: Solve for x
    x = 167,859.40/398.09
  6. Step 6: Final answer
    x = 421.66

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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.