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Finding the Fourth Proportional to 421.71, 582.12 and 287.16

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Solution

The fourth proportional to 421.71, 582.12 and 287.16 is: 396.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.71 : 582.12 = 287.16 : x
  2. Step 2: Convert to fraction form
    421.71/582.12 = 287.16/x
  3. Step 3: Cross multiply
    421.71x = 582.12 × 287.16
  4. Step 4: Simplify right side
    421.71x = 167,161.58
  5. Step 5: Solve for x
    x = 167,161.58/421.71
  6. Step 6: Final answer
    x = 396.39

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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.