Grade 7

2. Geometric figures commonly used in drawing lines, angles, quadrilaterals, regular
polygons, circles and arcs and solids.
Line – is a set of points. A portion of the line between two distinct points is called a
line segment.
1. Straight line – is the shortest distance between two points.
2. Parallel lines – are lines on the same plane which will not meet no matter how
long you extend them.
3. Perpendicular lines – are two intersecting lines which form right angles.
Angle – is a figure formed by two rays with common end point.
1. Straight angle – an angle whose measure is 180o.
2. Right angle – an angle whose measure is 90o.
3. Acute angle – an angle whose measure is less than 90o.
4. Obtuse angle – an angle whose measure is more than 90 but less than 180o.
5. Complimentary angles – two angles whose sum measures 90o.
6. Supplementary angles – two angles whose sum measures 180o.

3. Polygon – is a closed figure formed by line segments intersecting at end points.
The line segments are called sides of the polygon. Polygon is classified according
to the number of sides.
Triangle – is a three-sided polygon.
Quadrilateral – is a four-sided polygon.
Pentagon – is a five-sided polygon. If the all sides of the pentagon are equal it is a
regular pentagon the measure of each inclined angle is 108o.
Hexagon – is a polygon with six sides. The measure of each included angle of a
hexagon is 120o.
Heptagon – is a polygon with seven sides. If all the sides and angles are equal, it
is a regular heptagon and the measure of each angle is approximately equal to
128.56o.
Octagon – a polygon with eight sides. The measure of each included angle is 135o.
Nonagon – nine sides. The measure of each included angle is 140o.
Decagon – ten sides. The measure of each included angle is 144o.

4. Circle – is a closed curved, all points are equidistant from the center.
Arc – is a portion of the circumference of a circle.
Solid – is a three-dimensional figure. The three dimensions are length, width and height.
Grades of pencil
1. Soft – 2B, 3B, 4B, 5B(Softest).
2. Medium – 3H, 2H, H, F, HB, B
3. Hard – 4H, 5H, 6H, 7H, 8H, 9H(Hardest)
Grades of Pencil used for General Drafting(Drawing)
HB – used for lettering.
2H – used for line work.
4H – used for general layout purposes.
Minimum requirement for drafting students
4H – for re-penciling light finished lines.
F or H – for all lettering and freehand work.
6H – for light construction lines in layout work where accuracy is required.
2H – for visible object lines.