jika panjang AE = 2/5 CE, keliling layang2 ABCD = ....

teorema phythagoras
AD² = AE² + ED²
10² = AE² + 8²
AE² = 100 - 64 = 36
AE = 6 cm

AE = 2/5 x CE
6 x 5 = 2 x CE
CE = 15 cm

BC² = BE² + EC²
BC² = 8² + 15² = 64 + 225 = 289
BC = 17 cm

keliling = 2 x BC + 2 x AB
keliling = 2 x 17 + 2 x 10 = 54 cm

#semoga membantu

ae=√10²-8²
    =√100-64
    =√36
     = 6 cm
ae=2/5 ce
 ce =5/2ae =5/2 x 6 =15 cm

dc=√15+8²
    =√225+64
    =√289
    =17 cm 
k=2(10+17)
  =2(27)
  =54 cm 
jawab.D