Find the perimeter of a regular octagon with a side length of 20
options:
120
140
160
180

perimeter of regular octagon is given as

= 8a

where a is side of regular octagon

so

perimeter = 8 x 20 = 160

so option c is answer

y < -3

step-by-step explanation:

-3y - 2 > 7

-3y -2 + 2 > 7+2

-3y > 9

-3y/-3 < 9/-3   (change the inequality sign when multiplying or dividing by a negative number)

y < -3

according to the triangle sum theorem, all the angles in a triangle must add up to 180 degrees. if we know one angle is already 90, we do 180-90=90. the other 2 angles must add up to 90, exactly.

step-by-step explanation: