In ΔABC and ΔDEF, if ∠A ≅ ∠D, ∠B ≅ ∠E, and ∠C ≅ ∠F, is ΔABC ≅ ΔDEF? Justify your answer.
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What is the resultant vector when a vector of magnitude 10 units, directed at 30 degrees from the positive x-axis, is added to a vector of magnitude 7 units, directed at 60 degrees from the positive x-axis?
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What is the formula for calculating the lateral surface area of a cone?