Solution

155311

First name
Alan
School
The Mall
Country
Age
13

1.
3+4+5 = 12
a=3, b=4, c=5

36-6c = ab/2
6=ab/2

12 = ab

2.
5+12+13=30
a=5, b=12, c=13

225 - 15c = ab/2
450-30c = ab
450-390 = ab
therefore ab = 60 = 5 x 12

3.
a=(p/2)^2 - (pc/2)

a=(p^2)/4 - (pc/2)

a=p/2(p/2-c)