The exterior angle of a triangle is 119° and its interior opposite angle are in the ratio 8: 9. find the angle of a triangle

see explanation

Step-by-step explanation:

the ratio of the opposite interior angles = 8 : 9 = 8x : 9x

The exterior angle of a triangle = sum of the opposite interior angles, hence

8x + 9x = 119

17x = 119 ( divide both sides by 17 )

x = 7

8 parts = 8x = 8 × 7 = 56

9 parts = 9x = 9 × 7 = 63

The sum of the 3 angles in a triangle = 180°

subtract the sum of the 2 angles from 180 for third angle in triangle

180° - (56 + 63)° = 180° - 119° = 61°

The 3 angles of the triangle are 56°, 61°, 63°

a 4/6 = 9/12   not proportional

step-by-step explanation:

to find which are not proportional, we can use cross products

if it is true, they are proportional.   if it is not true, they are not proportional.

a 4/6 = 9/12

4* 12 = 6*9

48 = 54

not this is not proportional  

b 2/3 = 12/18  

2* 18 = 3 * 12

36 = 36

this is proportional

c 5/4 = 10/8  

5*8 = 4*10

40 = 40

this is proportional

d 7/5 = 35/25

7*25 = 5 * 35

175 = 175

is proportional

144.50

step-by-step explanation:

21.5 x 13.4=288.10 divide by 2