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Finding the Fourth Proportional to 398.76, 549.88 and 315.60

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Solution

The fourth proportional to 398.76, 549.88 and 315.60 is: 435.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    398.76 : 549.88 = 315.60 : x
  2. Step 2: Convert to fraction form
    398.76/549.88 = 315.60/x
  3. Step 3: Cross multiply
    398.76x = 549.88 × 315.60
  4. Step 4: Simplify right side
    398.76x = 173,542.13
  5. Step 5: Solve for x
    x = 173,542.13/398.76
  6. Step 6: Final answer
    x = 435.20

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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.