Tolong dijawab no 13, 14, & 15 please

Jawaban:

13. krn sdt ABC adl 180 drjt, maka :

SdtABC = sdtABE + sdtDBE + sdtCBD

180 = 2x – 1 + 60 + 3x + 6

180 = 5x + 65

5x = 180 – 65

5x = 115

x = 115/5 = 23

subtitusikn nilai ke :

sdtCBD = 3x + 6

= 3 . 23 + 6

= 69 + 6

= 75 drjt