A straight-edge
Surface area
The side opposite the right angle is called the hypotenuse.
vertex
Two lines that form a right angle at their point of intersection is called perpendicular lines.
An angle measuring more than 90 degrees is obtuse. An angle measuring less than 90 degrees is acute. An angle measuring 90 degrees is right.
pictograph
A pyramid perhaps
An equilateral parallelogram is called a rhombus.
A triangle is a geometric figure that is made of three line segments. It is a closed figure and has three angles.
It is a circle or a sphere
The circumference of a circle represents its perimeter and the distance around it.
Perimeter of triangle: 6+8+10 = 24 inches