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Finding the Fourth Proportional to 431.42, 646.34 and 286.78

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Solution

The fourth proportional to 431.42, 646.34 and 286.78 is: 429.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.42 : 646.34 = 286.78 : x
  2. Step 2: Convert to fraction form
    431.42/646.34 = 286.78/x
  3. Step 3: Cross multiply
    431.42x = 646.34 × 286.78
  4. Step 4: Simplify right side
    431.42x = 185,357.39
  5. Step 5: Solve for x
    x = 185,357.39/431.42
  6. Step 6: Final answer
    x = 429.64

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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.