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Finding the Fourth Proportional to 431.44, 645.64 and 258.21

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Solution

The fourth proportional to 431.44, 645.64 and 258.21 is: 386.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.44 : 645.64 = 258.21 : x
  2. Step 2: Convert to fraction form
    431.44/645.64 = 258.21/x
  3. Step 3: Cross multiply
    431.44x = 645.64 × 258.21
  4. Step 4: Simplify right side
    431.44x = 166,710.06
  5. Step 5: Solve for x
    x = 166,710.06/431.44
  6. Step 6: Final answer
    x = 386.41

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.