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Finding the Fourth Proportional to 431.12, 643.42 and 419.60

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Solution

The fourth proportional to 431.12, 643.42 and 419.60 is: 626.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.12 : 643.42 = 419.60 : x
  2. Step 2: Convert to fraction form
    431.12/643.42 = 419.60/x
  3. Step 3: Cross multiply
    431.12x = 643.42 × 419.60
  4. Step 4: Simplify right side
    431.12x = 269,979.03
  5. Step 5: Solve for x
    x = 269,979.03/431.12
  6. Step 6: Final answer
    x = 626.23

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.