##### Across

**2.**The angle cut out of a piece of paper so that the paper can be rolled into a right circular cone**5.**a line that touches a curve at only one point**6.**a straight line passing through the center of a circle or sphere and meeting the circumference or surface at each end**7.**a quadrilateral with two pairs of adjacent sides with equal lengths**10.**A triangle that has 2 equal sides**11.**a polygon is scalene if its sides are all different lengths**12.**the trigonometric function that is equal to the ratio of the side adjacent to an acute angle (in a right-angled triangle) to the hypotenuse**13.**The union of a circle and its interior**14.**extending or lying across**15.**In a right angle triangle the side of the triangle that is opposite to the right angle**16.**a curve that is continuous and has endpoints that meet at the same point**20.**covering of the plane, sometimes referred to as a tiling,referring to the way that tiles cover a floor

##### Down

**1.**a triangle which all the sides are congruent**3.**The meeting point of the three medians of a triangle. This point is the center of mass of the triangle**4.**A segment that connects any vertex of a triangle to the midpoint of the opposite side**8.**the boundary of a simple two-dimensional region,including shapes with straight and curved sides**9.**ratio of the length of the side opposite the given angle to the length of the hypotenuse of a right-angled triangle**17.**polygon has no diagonal with points outside the polygon**18.**A triangle that has no equal sides. All 3 sides are different lengths**19.**Two points directly opposite each other on a sphere