First one:
cos(A)=AC/AB=3/4.24
cos(B)=BC/AB=3/4.24
Cos(A)/cos(B)=AC/AB / (BC/AB) = AC/AB * AB/BC = AC/BC=3/3=1
Second one:
To solve this problem, we have to ASSUME AFE is a straight line, i.e. angle EFB is 90 degrees. (this is not explicitly given).
If that's the case, AE is a transversal of parallel lines AB and DE.
And Angle A is congruent to angle E (alternate interior angles).
Therefore sin(A)=sin(E)=0.5
If QR is a median, then:

We have NO = 30, MP = 9x - 42 and QR = x + 15. Substitute:

<h3>Answer: A. 6</h3>
The above figure can be formed into a cube.
This is for any polyhedron that does not intersect itself. The Euler's formula states that the number of faces plus the number of vertices or corner points less the number of edges is always equal to 2.
Faces + Vertices - Edges = 2
A cube has 6 faces, 8 vertices, and 12 edges.
Euler's formula: 6 + 8 - 12 = 2 ⇒ 14 - 12 = 2 ⇒ 2 = 2
You did good, it IS correct.
Answer:
Area: ½ × base × height
Perimeter: sum of side lengths of the triangle
of vertices: 3
Number of edges: 3
Internal angle: 60° (for equilateral)
Sum of interior angles: 180°
Step-by-step explanation: