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Finding the Fourth Proportional to 431.40, 646.62 and 258.30

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Solution

The fourth proportional to 431.40, 646.62 and 258.30 is: 387.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.40 : 646.62 = 258.30 : x
  2. Step 2: Convert to fraction form
    431.40/646.62 = 258.30/x
  3. Step 3: Cross multiply
    431.40x = 646.62 × 258.30
  4. Step 4: Simplify right side
    431.40x = 167,021.95
  5. Step 5: Solve for x
    x = 167,021.95/431.40
  6. Step 6: Final answer
    x = 387.16

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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.