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Finding the Fourth Proportional to 431.02, 643.60 and 338.68

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Solution

The fourth proportional to 431.02, 643.60 and 338.68 is: 505.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.02 : 643.60 = 338.68 : x
  2. Step 2: Convert to fraction form
    431.02/643.60 = 338.68/x
  3. Step 3: Cross multiply
    431.02x = 643.60 × 338.68
  4. Step 4: Simplify right side
    431.02x = 217,971.23
  5. Step 5: Solve for x
    x = 217,971.23/431.02
  6. Step 6: Final answer
    x = 505.72

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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.