Answer:If it's less than 180 degrees, which it is, subtract 4π/5 π from (180 degrees) so π - 4π/5 is equal to π/5.
Step-by-step explanation:Quad. 1 For an angle, T, 0 < T< pi/2 then the ref angle = T Quad 2 For an angle, T, pi/2 < T< pi then the ref angle = pi - T Quad 3 For an angle, T, pi < T< 3pi/2 then the ref angle = T - pi Quad 4 For an angle, T, 3pi/2 < T< 2pi then the ref angle = 2pi - T