# Squareness

### From DT Online

**Squareness** refers to things being a right angles or 90 degrees to each other *(i.e. as the corners of a Square)*. Checking that something is

**Square**is a common designing and making requirement and operations often have to be performed at right angles to an edge or surface

*(e.g. marking a line, cutting material to length, drilling a hole)*.

**Carpenters** and **Engineers** use a **Try Square** to draw or scribe lines at right angles to an edge or to test if a corner is **Square**. They may also use a **Framing Square** to check that corners of a larger construction are **Square** - but this can also be done by testing that its **Diagonals** are of equal length *(since this is a characteristic of all squares and rectangles).*

**Note:**
The **Diagonals** of an **Isosceles Trapezium** are also equal so checking their length would also test if such a regular shape was **‘squared up’**

In **Technical Drawing** a **Draughtsman** would use a **T-square** pressed against the edge of a drawing board to draw parallel lines across the paper and place **Set Squares** to draw lines at 90deg, 45deg, 60deg, and 30deg to it.