🗺️ Chapter Roadmap
1 Lines & Angles
Geometry is the study of shapes and sizes. It all starts with a single point and a line. When two lines meet at a point, they create an Angle.
Acute Angle
Narrower than an L-shape.
Right Angle
A perfect L-shape (Corners).
Obtuse Angle
Wider than an L-shape.
Straight Angle
A perfectly flat straight line.
Reflex Angle
Bends backwards.
💡 Angle Pairs (NTS Favorites)
- Complementary Angles: Two angles that add up to 90°.
- Supplementary Angles: Two angles that add up to 180°.
2 Triangles
A triangle is a closed shape with 3 sides. The Golden Rule of triangles is that if you add all three inside angles, the sum is always 180°.
Equilateral
All 3 sides are equal. All 3 angles are 60° each.
Isosceles
Only 2 sides are equal. The 2 angles opposite those sides are also equal.
Scalene
No sides are equal. No angles are equal.
3 Pythagoras Theorem
This theorem only applies to Right-Angled Triangles (triangles with one 90° angle). It helps us find the length of a missing side.
The Formula
Base2 + Perpendicular2 = Hypotenuse2
If the sides are 3 and 4, the longest side (hypotenuse) will always be 5. Other common sets (triplets) are 6-8-10 and 5-12-13.
4 Circles
A circle has several parts that examiners love to ask about in MCQs:
Diameter = 2 × Radius
5 Area & Perimeter Basics
🔲 Square
Perimeter = 4 × side
Area = side × side (s2)
▭ Rectangle
Perimeter = 2(length + width)
Area = length × width