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Finding the Fourth Proportional to 312.59, 431.37 and 188.21

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Solution

The fourth proportional to 312.59, 431.37 and 188.21 is: 259.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    312.59 : 431.37 = 188.21 : x
  2. Step 2: Convert to fraction form
    312.59/431.37 = 188.21/x
  3. Step 3: Cross multiply
    312.59x = 431.37 × 188.21
  4. Step 4: Simplify right side
    312.59x = 81,185.99
  5. Step 5: Solve for x
    x = 81,185.99/312.59
  6. Step 6: Final answer
    x = 259.72

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.