If rb = 5, then ab = ?
a. 2.5
b. 5
c. 10

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.

step-by-step explanation:

is their an equation anywhere i can take a   look at it and see if i am right.

on the middle line

step-by-step explanation:

1/5=50

can i see a photo of the question so i can you?