7. Find: (i) x + y +z (ii) a+b+c+d

Q.1 360° Q.2 360°

Step-by-step explanation:

Q.1 let the third angle of the triangle be a

70°+40°+a=180(by angle sum property)

110°+a=180

a=180°-110°

a=70°

angle x=70°+x=180°(linear angle)

x=180°-70°

x=110°

angle z= 40°+z=180

z= 180°-40°

z=140°

angle y=a+y=180°

70°+y=+80°

y=180°-70°

y=110°

y+z+x=110° +110° +140°=360

Q.2 let the fourth angle of the quadrilateral be x

120°+70°+60°+ x=360° (by angle sum property)

250°+x=360°

x=360°-250°

x=110°

angle a=120°+a=180°(by linear angle)

a=180°-120°

a=60°

angle b=70°+b=180°

b=180°-70°

b=110°

angle c=x+c=180°

110° + c=180°

c=180°-110°

c=70°

angle d=60°+d=180°

d= 180° -60°

d=120°

a+b+ c+d=120°+110°+60°+70°=360°

ok

step-by-step explanation: