# Math help from the Learning Centre

This guide provides useful resources for a wide variety of math topics. It is targeted at students enrolled in a math course or any other Centennial course that requires math knowledge and skills.

## 2-D Shapes

quadrilateral is a closed 2-D figure with four straight sides ("quad" means four and "lateral" means side).

 Some properties of quadrilaterals have are: Four sides (edges) Four vertices (corners) Interior angles that add to $$360^{\circ}$$ There are a few special quadrilaterals with specific names based on their properties: Rectangle Square Parallelogram Rhombus Trapezoid

Tip: Based on their properties, all rectangles, squares, and rhombuses are parallelograms, but not all parallelograms are rectangles/squares/rhombuses! Similar idea occurs with rectangles and squares - all squares are rectangles, but not all rectangles are squares.

Triangles

 When the base and height of a triangle are given, the area is calculated as: $$Area=\frac{1}{2} \times base \times height$$                                              $$=\frac{1}{2}bh$$ When all the side lengths of the triangle are given, the area is calculated using Heron's Formula: $$Area=\sqrt{s(s-a)(s-b)(s-c)}$$, where $$s=\frac{1}{2}(a+b+c)$$

Circles

 Arc Any connected part between two points on a circle. Chord A line segment whose endpoints lie on the circle (divides a circle into two segments). Radius The straight-line segment that connects a centre of the circle to a point on a circle. Sector A figure formed by two radii and an arc (determined by the endpoints of the radii). Segment A figure formed by an arc and chord joining the endpoints of the arc.

## 3-D Figures

 Vertex (Vertices) A point where two or more line segments meet (i.e. a corner). Edge (Edges) A line segment joining one vertex/corner to another or a line segment where two faces meet. Face (Faces) Any individual flat surface of a 3D figure. Surface Area Total area of the surfaces of a 3D figure. Lateral Area Surface area of a 3D figure, excluding its base and top (when they exist). Volume The amount of 3D space that is occupied/taken up by a 3D figure.

Example 1