Answer:
the missing side lenght = x
0 < x < 15+10
0 < x < 25 cm
We know that
The Euler's formula state that, the number of vertices, minus the number of edges, plus the number of faces, is equal to two
V - E + F = 2
clear F
F=2-V+E
in this problem
V=8
E=14
F=?
so
F=2-8+14
F=8
the answer is8 faces
Y - y1 = m (x - x1)
y1 being the y coordinate
x1 being the x coordinate
m being the gradient (or slope)
y - - 1 = -8 (x - 2)
y + 1 = -8x + 16
y = -8x + 15
