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Finding the Fourth Proportional to 398.58, 549.97 and 221.51

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Solution

The fourth proportional to 398.58, 549.97 and 221.51 is: 305.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    398.58 : 549.97 = 221.51 : x
  2. Step 2: Convert to fraction form
    398.58/549.97 = 221.51/x
  3. Step 3: Cross multiply
    398.58x = 549.97 × 221.51
  4. Step 4: Simplify right side
    398.58x = 121,823.85
  5. Step 5: Solve for x
    x = 121,823.85/398.58
  6. Step 6: Final answer
    x = 305.64

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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.