What is the measure of

81

Step-by-step explanation:

From the diagram,

143 is the exterior angle of the triangle.

61 and B are interior angles of the triange.

Formula : -

Exterior angle of a triangle = Sum of two interior angles in a triangle

143 = 61 + ∠B

∠B = 143 - 61

∠B = 82

Therefore, the measure of ∠B is 82.

no one knows lol

step-by-step explanation:

see explanation

step-by-step explanation:

a

(6r + 7) + (13 + 7r) ( remove brackets and collect like terms )

= 6r + 7 + 13 + 7r

= 13r + 20

b

remove brackets and collect like terms

13 - r - 1 + r

= 12 - r

c

remove brackets and collect like terms

= - 8 - r + 2r - 4

= - 12 + r

d

remove brackets and collect like terms

= 7r - - - 6r

[-   - = - - = - ]

= r -