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Finding the Fourth Proportional to 312.61, 431.28 and 188.22

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Solution

The fourth proportional to 312.61, 431.28 and 188.22 is: 259.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    312.61 : 431.28 = 188.22 : x
  2. Step 2: Convert to fraction form
    312.61/431.28 = 188.22/x
  3. Step 3: Cross multiply
    312.61x = 431.28 × 188.22
  4. Step 4: Simplify right side
    312.61x = 81,175.52
  5. Step 5: Solve for x
    x = 81,175.52/312.61
  6. Step 6: Final answer
    x = 259.67

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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.