1a. panjang BD = 6cmb. luas=1/2 . d1 . d2 = 1/2 . 6.6 = 18 cm22.keliling persegi=keliling persegi panjang40 cm = 2l.2p40 cm = (2.5 ).2p40 cm = 10 . 2p40 – 10=2p30 = 2pp = 153. a. panjang PQ = akar 9 pngkt 2 + 12 pngkt 2 = 15cmb. QT+TS =12+40 = 52 cmc.pnjang PQ = 15panjang QR =PQ = 15panjangRS = akar 40 pngkt 2 + 9 pngkt 2 = 41 cmpanjangSP = RS = 41 cmkeliling = 15+15+41+41=112 cm, 1. a.misalnya titik potong AC dan BD adalah O, maka panjang BO =, =, =, = 4, Panjang BD = 2BO, =2\xd7 4 = 8 cm, b. Lbelah ketupat =, =, =, = 24 cm\xb2, 2. K persegi = K persegi panjang, 4s = 2p + 2l, 40 = 40, 40 = 2p + 2\xd75, 40= 2p + 10, 40 – 10 = 2p, 30 = 2p, p =, = 15 cm., 3. a.panjangPQ=, =, =, = 15, b. Panjang QS = panjang QT + panjang ST, = 40 + 12, = 52 cm, c. KLayang – layang = 2PQ + 2PS, = 2\xd715 + 2\xd741, = 30 + 82, = 112 cm, Panjang PS =, =, =, = 41 cm, Semoga membantu dan jadi yang terbaik ya~