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Finding the Fourth Proportional to 287.60, 431.40 and 206.60

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Solution

The fourth proportional to 287.60, 431.40 and 206.60 is: 309.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    287.60 : 431.40 = 206.60 : x
  2. Step 2: Convert to fraction form
    287.60/431.40 = 206.60/x
  3. Step 3: Cross multiply
    287.60x = 431.40 × 206.60
  4. Step 4: Simplify right side
    287.60x = 89,127.24
  5. Step 5: Solve for x
    x = 89,127.24/287.60
  6. Step 6: Final answer
    x = 309.90

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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.