A quadrilateral I believe.
The other dog's age is "x". Rex's puppy is 5 years less than "x". SO...
x-5.
Understand?
First we will convert those radian angles to degrees, since my mind works better with degrees. Let's work one at a time. First,

. If we start at the positive x-axis and measure out 315 we end up in the 4th quadrant with a reference angle of 45 with the positive x-axis. The side across from the reference angle is -1, the side adjacent to the angle is 1, and the hypotenuse is sqrt2. The cotangent of this angle, then is 1/-1 which is -1. As for the second one, converting radians to degrees gives us that

. Sweeping out that angle has us going around the origin more than once and ending up in the first quadrant with a reference angle of 30° with the positive x-axis. The side across from the angle is 1, the side adjacent to the angle is √3, and the hypotenuse is 2. Therefore, the secant of that angle is 2/√3.
It is best to use mental math with some equations (5x5 or something that is easy enough that work does not have to be shown 10 dived by 5
4 x 0.90 = £3.60
£13.50 - £3.60 = £9.90
0.9 + 0.75 = £1.65
£9.90/£1.65 = 6
They bought 6 ice cream cones