B because absolute value means the distance of a point on a number line from 0. So the absolute value of -6 is 6 and you add that to 4
The perimeters of two opposite triangular faces includes all 4 slant edges and 2 of 4 base edges. The other two base edges are half the base perimeter, so the total length of all edges is
.. 2*(27.5 cm) +(1/2)*(30 cm) = 70 cm
1/2 = 2/4
1/3 = 2/6
3/4 = 9/12
2/5 = 4/10.
hope that helped