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Finding the Fourth Proportional to 290.20, 431.58 and 287.18

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Solution

The fourth proportional to 290.20, 431.58 and 287.18 is: 427.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    290.20 : 431.58 = 287.18 : x
  2. Step 2: Convert to fraction form
    290.20/431.58 = 287.18/x
  3. Step 3: Cross multiply
    290.20x = 431.58 × 287.18
  4. Step 4: Simplify right side
    290.20x = 123,941.14
  5. Step 5: Solve for x
    x = 123,941.14/290.20
  6. Step 6: Final answer
    x = 427.09

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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.