5.
A = 8*5 = 40
P = 8+5+8+5 = 26
7.
x = √(10²-6²) = √100-36 = √64 = 8
A = (6*8)/2 = 48/2 = 24
9.
x = √(5²+12²) = √(25+144) = √169 = 13
11.
x = √(3²+4²) = √(9+16) = √25 = 5
