Answer:
Step-by-step explanation:
To calculate this we use Pythagoras' theorem: a^2+b^2=c^2
in this case a=8cm, b=5cm and c=22
so we do 8^2+5^2=89
the square root of 89 is 9.4 (1 d.p)
8+5+9.4=22.4 so rounded (22), this triangle is a right-angled triangle since Pythagoras theorem has proved ABC is a right-angled triangle
