Graph the line with the slope -1 passing through the point (5,4)

y - y1 = m(x - x1)

y - 4 = -1(x - 5)

y - 4 = -x + 5

y = -x + 9

(0, 9) is the y-intercept

Basic points on the graph:

(1, 8)

(-1, 10)

(2, 7)

(3, 6)

< coa = 150 ( given)

as ba and bc are tangents

so oc and oa is perpendicular to cb and ab respectively because in circle normal passes through centre

so in quadrilateral oabc

< coa + < oab + < ocb + < abc = 360

150 +90+90 + < abc = 360

330 + < abc = 360

< abc = 360 -330 = 30

so < abc = 30

⭐dhruv⭐

2.2°  

step-by-step explanation:

let θ = the angle of elevation.

tanθ =77/2020

tanθ = 0.038 12

      θ = tan⁻¹0.038 12

      θ = 2.2°