a) 9 toilet rolls cost $ 4.23
1 toilet roll costs $ x
9x = 4.23 * 1
x= 4.23 / 9
x = 0.47
So in first case one toilet roll costs $ 0.47.
b) 4 toilet rolls cost $1.96
1 toilet roll costs $ x
4x = 1.96 * 1
x = 1.96 / 4
x = 0.49
So in second case one toilet roll costs $ 0.49.
0.47 < 0.49
The toilet roll in first case is cheaper than the toilet roll in second case.
Hope this heps!
Answer:

Step-by-step explanation:
The standard form of an equation of a circle:

(h, k) - center
r - radius
We have the endpoints of the diameter of a circle (-8, -6) and (-4, -14).
The midpoint of a diameter is a center of a circle.
The formula of a midpoint:

Substitute:

We have h = -6 and k = -10.
The radius is the distance between a center and the point on a circumference of a circle.
The formula of a distance between two points:

Substitute (-6, -10) and (-8, -6):

Finally we have

Answer:
8 units.
Step-by-step explanation:
The smaller of the right triangles formed is similar to the whole triangle so
4/x = x/16 where x = the shorter leg
x^2 = 64
x = 8.