Apolygon with all sides tangent to a circle contained within the polygon
common external tangent
2.
the common tangent intersecting the line segment joining the centers of circles
common internal tangent
3.
a common tangent that does not intersect the line segment joining the centers of circles
tangent line
4.
a line in the plane of a circle that intersects the circle in exactly one point
circumscribed polygon

1.  circumcised

2.  common internal

3. common external

4. tangent line

hope this helps :)

b. an equilateral triangle inscribed in a circle

step-by-step explanation:

we are given the figure of two circles having a triangle inside.

now, we know that,

"when a figure is lying inside an another figure, then the outside figure is known as circumscribed figure and the figure lying inside is referred to as the inscribed figure".

as we see that, the circles are containing the triangle completely.

thus, the circles are the circumscribed figures and the triangle is the inscribed figure.

hence, we get, 'an equilateral triangle is inscribed in a circle'.