Answer:
y=3
Step-by-step explanation:
(i used point-slope form which is (y1-y2)=m(x1-x2))
(10-y)=7(4-3)
10-y=7
-y=-3
y=3
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Answer:

Step-by-step explanation:
to find the surface area we need to find the followng areas:
- area of a triangle and multiply it by 4 (because there are 4 triangles)
And once we have those areas, we add them to find the surface area.
Area of the square:
the formula to find the area of a square is:

where
is the length of the side: 
thus the area of the square is:


Area of the triangles:
the are of 1 triangle is given by

where
is the base of the triangle:
(the base of the triangle is the side of the square)
and
is the height of the triangle: 
thus, the area of 1 triangle is:



the area of the 4 triangles is (we multiply by 4):


finally we add the area of the square and the area of the 4 triangles to find the total surface area:

