Answer: B. 18 units
Step-by-step explanation:
The triangle can be divided into two right angle triangles whose height is 3 units and the upper width is 4 units.
Using pythagora's theorem to find the slant side (hypotenus) of each right angle triangle
y^2 = 4^2 + 3^2 = 25
y = 5 units.
The total width of the upper side of the triangle is 8 units,
The perimeter is the addition of all the sides of the triangle which is;
8 units + 5 units + 5 units = 18 units
See image below
