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Finding the Fourth Proportional to 398.42, 549.48 and 305

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Solution

The fourth proportional to 398.42, 549.48 and 305 is: 420.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    398.42 : 549.48 = 305 : x
  2. Step 2: Convert to fraction form
    398.42/549.48 = 305/x
  3. Step 3: Cross multiply
    398.42x = 549.48 × 305
  4. Step 4: Simplify right side
    398.42x = 167,591.40
  5. Step 5: Solve for x
    x = 167,591.40/398.42
  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.