A, b and d are points on the circumference of a circle centre o.
edc is a tangent to the circle.
angle bdc = 57°
find the size of angle aob.
you must give a reason for each stage of your working.

5

step-by-step explanation:

  q

step-by-step explanation:

each line from a vertex to the midpoint of the opposite side is called a median. the point where the medians intersect, point q, is the centroid.

the centroid of δabc is point q.

x = -4

step-by-step explanation:

- 20 - 4(x + 3) = 4x

=> -20 - 4x - 12 = 4x

=> - 32 -4x = 4x

=> -32 = 4x + 4x

=> - 32 = 8x

=> -32/8 = x

=> -4 = x