Answer:
0.3cm ?
Step-by-step explanation:
The perimeter is just all the lines around the outside of the shape so basically take all the numbers and add them together to get the answer
I don't know if my answer is completely correct, but I think it's 100. All triangles add up to 180, and an isosceles triangle has 2 equal sides. 40 would be the 2 sides, and 180 subtracted from 80 equals 100.