Answer:
yes it is parallel because the alternate interior angles are equal
Answer:
Triangle A: 38 degrees
Triangle B: Unknown (not enough information)
Triangle C: Unknown (not enough information)
Triangle D: 70 degrees
Triangle E: 40 degrees
Step-by-step explanation:
Work for Triangle A: 90 + 52 = 142. 180 - 142 = 38.
Work for Triangle B: Unidentifiable because there is no indicator to tell you if any of the angles/lines are equal. Generally there will be a "double lined" indicator in the corners of which a triangles angles are equal.
Work for Triangle C: Same as B.
Work for Triangle D: 90 + 20 = 110. 180 - 110 = 70.
Work for Triangle E: 90 + 50 = 140. 180 - 140 = 40.
The answer is the option A, which is: A. Equilateral triangles.
The explanation for this answer is shown below:
By definition, a tetrahedron is a solid in three dimensions that has: six sides, four vertices and four triangular faces. These faces are equilateral triangles, which means that all the sides are equal and all the interior angles measure 
degrees.
The tetrahedron is also called "triangular pyramid".
