the triangle shown in the middle is a 45-90-45 degree triangle ( the orange lines on the legs mean legs are equal)
so if you were to mirror it there would be 90 degrees between A & B
answer is 90 degrees
We are given
selling price of one flower is $0.50
so, 
Let's assume
she sold 'n' flowers to get $20
so, total amount she get after selling 'n' flowers is


This is supposed to be $20
so, we can set it equal to 20

now, we can solve for n
we get

we are given
she makes $6.00 on every $20 worth sold
so, we can find cost of 40 flowers is 20-6
total cost is 14
or cost of 40 flowers is $14
now, we can find cost of one flower


so, cost of each flower is 35 cents...............Answer
ok so what you wanna do is use multiplication