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Finding the Fourth Proportional to 398.16, 549.24 and 309.60

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Solution

The fourth proportional to 398.16, 549.24 and 309.60 is: 427.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    398.16 : 549.24 = 309.60 : x
  2. Step 2: Convert to fraction form
    398.16/549.24 = 309.60/x
  3. Step 3: Cross multiply
    398.16x = 549.24 × 309.60
  4. Step 4: Simplify right side
    398.16x = 170,044.70
  5. Step 5: Solve for x
    x = 170,044.70/398.16
  6. Step 6: Final answer
    x = 427.08

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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.