Tolong kak sama cara nya ​

Jawaban:

1. a. ABC = 180 – CBD

ABC = 180 – 115

ABC = 65

b. 2x – 5 + 3x + 15 + 65 =180

5x + 75 = 180

5x = 105

x = 21

BAC = 2x – 5 = 2(21)-5 = 37

2. a. Luas PQR

= 1/2 x PR x QR

= 1/2 x 12 x 16

= 96 cm²

b. 1/2 x PQ x RS = 1/2 x PR x QR

1/2 x 20 x RS = 1/2 x 12 x 16

10 RS= 96

RS = 9,6 cm

3. Keliling ABC = 102 cm

AB + BC + AC = 102 cm

AB + 40 + 26 = 102

AB + 66 = 102

AB = 36 cm

OC = √(AC² – OA²)

OC = √(26² -10²)

OC = √576

OC = 24 cm

Luas ABC

= 1/2 x AB x OC

= 1/2 x 36 x 24

= 432 cm²