Hellpp please 20 points for that

a) 12cm

b) 360cm²

c) 2160cm cubed

Step-by-step explanation:

a)

you would use Pythagoras theorem  for A

so half of 18 is 9

15² - 9² = 144

the square root of 144 is 12

the height is 12cm

b)

18 x 20 = 360cm²

c)

csa x L

csa = b x h divide by 2

18 x 12 = 216cm²/2 = 108cm²

108xm² x 20cm = 2160cm cubed

i dont get the question

step-by-step explanation:

second option

step-by-step explanation:

the measures of a triangle equal 180. use that to find x.

2x+3x+4x=180

9x=180

9x/9=180/9

x=20

now you know x, you know angle a is 40°, angle b is 60°, angle c is 80°.

because angle a is 40°, the first option doesn't work.

because angle b is 60°, the second option does work.

when you add angle a and b, you get 100°. complementary means it equals 90°, so the third option doesn't work.

when you add angle a and c, you get 120°, which is not 100.