bantu nomer 3 kak thx

3.1
x = (akar) 20^2 - 12^2
= (akar) 400-144
= (akar) 256
x = 16

3.2
sisi tegak = (akar)13^2-5^2
= (akar)169-25
= (akar)144
= 12
× = (akar)12^2+35^2
= (akar)144+1225
= (akar)1369
= 37