How to find cos(a) if tan (a) = 0.5 and a is in the III quadrant

Hope for an explanation
If the exercise was explained poorly the write it in the comments or sth like that

hey

Step-by-step explanation:

tana=5/10

tan a=1/2

I\

1 I \ x

I \

I__a\

2

Let unknown side be x

angle be a

using pythagorus theorem,1²+2²=x²

x²=5

x= √5,-√5

cos a= 2/√5

but a is in quadrant III ,Cos is negative

-1, -2, -3, -4, -6

step-by-step explanation:

answer: the price of one pound cabbage = $ 0.8

the point (10,8) represents that the cost of 10 pounds cabbage is $ 8

step-by-step explanation:

since, here is a proportional relation between the number of pounds of cabbage (x) and the price in dollars (y).

therefore, we can write,

⇒ y = k x

where k is the constant of proportionality.

now, point (5,4) is in the line.

thus, it will satisfies the above equation of line.

⇒ 4 = 5 k

⇒ k = 0.8

thus, the equation of the line is,

y = 0.8 x

a) for x = 1,

y = 0.8

therefore, the cost of one pound of cabbage is 0.8 dollars.

b) in the below graph (10,8) represents that the cost of 10 pounds of cabbage is 8 dollars.