Answer:

Step-by-step explanation:
Given
The attached triangle
Required
Find y
The attached triangle is isosceles; so:

Also, we have:
--- angles in a triangle
Substitute: 

Collect like terms


The vertex would be (-2,4)
Answer:
H=13cm
Step-by-step explanation:
Volume= Length x Width x Height
v=624cm^3
L=8cm
W=6cm
8cm x 6cm=48cm^2
Divide 624cm^3 by 48cm^2= 13cm
H=13cm
Hope this helps!