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Finding the Fourth Proportional to 631.42, 872.09 and 421.25

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Solution

The fourth proportional to 631.42, 872.09 and 421.25 is: 581.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    631.42 : 872.09 = 421.25 : x
  2. Step 2: Convert to fraction form
    631.42/872.09 = 421.25/x
  3. Step 3: Cross multiply
    631.42x = 872.09 × 421.25
  4. Step 4: Simplify right side
    631.42x = 367,365.81
  5. Step 5: Solve for x
    x = 367,365.81/631.42
  6. Step 6: Final answer
    x = 581.81

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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.