Penjelasan dengan langkah-langkah:

1.

5x-2 +3x -8 + 2x-10 =180

10x -20 = 180

10x = 180 +20

10x = 200

x = 20°

2.

60 +6x + 4x =180

60 + 10x = 180

10x = 180-60

10x = 120

x = 120÷10

x = 12°

< PQR = 4x = 48°

3.

(i) 2² + 3² = 5²

4 + 9 = 25

13 < 25 segitiga tumpul

(ii) 3² + 4² = 6²

9 + 6 = 36

15 < 36 segitiga tumpul

(iii) 7² + 8² = 12²

49 + 64 = 144

113 < 144 segitiga tumpul

(iv) 7² + 24² = 25²

49 + 576 = 625

625 = 625 siku-siku

4. C

5.

p = 7+L

Kell = 2× ( p+L)

38 = 2 × (7+L +L)

38 ÷2 = 7 +2L

19 = 7+2L

19-7 = 2L

12 = 2L

L = 12÷2

L = 6 cm

p = 7+6 =13 cm

Luas = p x L

= 13 x 6

= 78 cm²

6.

P : L = 5 : 3

Kell = 96

2 x (P+L) = 96

P + L = 96÷2

P + L = 48

P = 5/8 × 48 = 30 cm

L = 3/8× 48 = 18 cm

7.

Luas = 121

sisi = 11 cm

Kell = 4xsisi

= 4 x 11 cm

= 44 cm

8. A

9.

(180° - 72) ÷2 = 108 ÷2 = 54°

Sudut yg lainnya = 54° dan 54°