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Finding the Fourth Proportional to 398.40, 549.78 and 286.38

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Solution

The fourth proportional to 398.40, 549.78 and 286.38 is: 395.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    398.40 : 549.78 = 286.38 : x
  2. Step 2: Convert to fraction form
    398.40/549.78 = 286.38/x
  3. Step 3: Cross multiply
    398.40x = 549.78 × 286.38
  4. Step 4: Simplify right side
    398.40x = 157,446.00
  5. Step 5: Solve for x
    x = 157,446.00/398.40
  6. Step 6: Final answer
    x = 395.20

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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.