1. You will have to find the height first which could be done by using pythagoras theorem
split the 12 by half giving 6
a^2 = b^2 + c^2
13^2 = 6^2+c^2
169 = 36+c^2
c^2=169-36
c^2=133
c=sqrt133
c= 11.53
area of triangle
1/2 x b x h
1/2 x 6 x 11.53
34.59
34.5(3 sf)
80 because when u do 10 times 8 it’s 80
P=2w+(2w-3)
60=4w-3
63=4w
15.75=w
l=2w-3
l=(2×15.75)-3
l=31.5-3
l=28.5
This answer doesn't add up so if you meant the COMBINED width then:
P=w+(2w-3)
60=3w-3
63=3w
21=w
l=2(21)-3
l=42-3
l=39
(This answer checks out so this is probably what you meant hope I helped)