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Finding the Fourth Proportional to 280.70, 386.92 and 221.59

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Solution

The fourth proportional to 280.70, 386.92 and 221.59 is: 305.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.70 : 386.92 = 221.59 : x
  2. Step 2: Convert to fraction form
    280.70/386.92 = 221.59/x
  3. Step 3: Cross multiply
    280.70x = 386.92 × 221.59
  4. Step 4: Simplify right side
    280.70x = 85,738.36
  5. Step 5: Solve for x
    x = 85,738.36/280.70
  6. Step 6: Final answer
    x = 305.45

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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.