dumatheresia
No. 39) 40 + 7x= 180 80 + 40 + 2y = 180 4z+60+40=180° x= (180-40)/7 2y = 180-80-40 4z= 180-60-40 x = 20° y = 60/2 = 30° z = 80/4 = 20° maka x + y + x = 20 + 30 + 20 = 70. no. 37) besar sudut a = d = h = 50° (didapat dari 180-80-50) sedangkan besar sudut b = c = 130° (didapat dari 180-50) besar sudut f = g = 80° dan e = 100° no.38 a) x = 105° b) x = 50° no.36a) 7x + 8 + 5x + 4 = 180° 12x= 180 - 12 12x = 168 x = 168/12 = 14° b) misalkan sudut C = c dan sudut B = b ⇒x + 40 + b = 180 ⇔x + b = 180 - 40 ⇔ x +b = 140 ⇒ b = 140 - x ⇒ 3x +30 + c = 180 ⇔ 3x + c = 180 - 30 ⇔ 3x + c = 150 ⇔ c = 150 - 3x 70 + c + b = 180° ⇒ 70 + 150 - 3x + 140 - x = 180 ⇒ -4x = 180 - 70 - 150 - 140 ⇒ -4x = -180 ⇒ x = -180/-4 = 45
2y= 180-80-40, y=30
7x = 2y + 4z
140 = 60 +4z, z=20
x+y+z = 70
x= (180-40)/7 2y = 180-80-40 4z= 180-60-40
x = 20° y = 60/2 = 30° z = 80/4 = 20°
maka x + y + x = 20 + 30 + 20 = 70.
no. 37) besar sudut a = d = h = 50° (didapat dari 180-80-50)
sedangkan besar sudut b = c = 130° (didapat dari 180-50)
besar sudut f = g = 80° dan e = 100°
no.38 a) x = 105° b) x = 50°
no.36a) 7x + 8 + 5x + 4 = 180°
12x= 180 - 12
12x = 168
x = 168/12 = 14°
b) misalkan sudut C = c dan sudut B = b
⇒x + 40 + b = 180 ⇔x + b = 180 - 40 ⇔ x +b = 140 ⇒ b = 140 - x
⇒ 3x +30 + c = 180 ⇔ 3x + c = 180 - 30 ⇔ 3x + c = 150 ⇔ c = 150 - 3x
70 + c + b = 180° ⇒ 70 + 150 - 3x + 140 - x = 180
⇒ -4x = 180 - 70 - 150 - 140
⇒ -4x = -180
⇒ x = -180/-4 = 45