Jawaban:
2) a. 24 cm
b. 29 cm
c. 14 cm
d. 29 cm
3) 7 cm
4) 156 cm²
5) a. p = 18 dan l = 9
b. k =54 cm
Penjelasan dengan langkah-langkah:
2)
a. K = 80 cm
p = 18 cm
l= ....?
K = 2 (p + l)
80 = 2 (18 + l)
80 = 32 + 2l
80 - 32 = 2l
48 = 2l
l = 48 : 2
l = 24 cm
b. K = 104 cm
l = 23 cm
p = ...?
K = 2 x (p + l)
104 = 2 x (p + 23)
104 = 2p + 46
2p = 104 - 46
2p = 58
p = 58 : 2 = 29 cm
c. K = 66 cm
p = 19 cm
l = ...?
K = 2 x (p + l)
66= 2 x (19 + l)
66= 38 + 2l
2l = 66 - 38
l = 28 : 2 = 14 cm
d. K = 110 cm
l = 26 cm
p = ...?
K = 2 x (p + l)
110= 2x (p + 26)
110 = 2p + 52
2p = 110- 52
p = 58 : 2 = 29 cm
3. L = 63
p = 9
lebar = Luas : panjang
l = L : p
= 63 : 9 = 7cm
4. K = 50 cm
p = 12 cm
ditanya Luas...?
- lebar
- K = 2(p + l)
- 50= 2(12 + l)
- 50= 24 + 2l
- 2l = 50 - 24
- l = 26 : 2
- l = 13cm
- Luasnya
- L = p x l
- = 12 x 13
- = 156 cm²
5. L = 162 cm²
p = 2 x l
a. tentukan p dan l
- L = p x l
- 162= (2 x l) x l
- 162= 2l x l
- 162= 2l²
- l² = 162 : 2
- l² = 81
- l = √81 = 9 cm
maka l atau lebar nya = 9 cm
- L = p x l
- 162 = p x 9
- p = 162 : 9
- p = 18
maka p atau panjangnya = 18 cm
b. tentukan kelilingnya
K = 2 x (p + l)
= 2 x (18+9)
= 36 + 18
= 54 cm
