tolong bantu ya tmn2 #beingserious

a. AB
cos a = samping/miring
cos a = AB/AC
cos 45° = AB/10
1/2√2 = AB/10
AB = 10√2/2
AB = 5√2

b. Luas = S x S
= 5√2 x 5√2
= 25 . 2
= 50 cm²
c. Keliling = 4 x S
= 4 x 5√2
= 20√2 cm

Maaf kalau salah :)