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Finding the Fourth Proportional to 398.98, 549.84 and 311.50

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Solution

The fourth proportional to 398.98, 549.84 and 311.50 is: 429.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    398.98 : 549.84 = 311.50 : x
  2. Step 2: Convert to fraction form
    398.98/549.84 = 311.50/x
  3. Step 3: Cross multiply
    398.98x = 549.84 × 311.50
  4. Step 4: Simplify right side
    398.98x = 171,275.16
  5. Step 5: Solve for x
    x = 171,275.16/398.98
  6. Step 6: Final answer
    x = 429.28

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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.