Geometry + Trigonometry (topic 3) Flashcards
1
Q
Midpoint
A
Halfway between two points
2
Q
Volume of a hemisphere
A
V = 2πr^3 / 3
3
Q
Right angle
A
90°
4
Q
Obtuse angle
A
θ > 90°
5
Q
Acute angle
A
θ < 90°
6
Q
To undo sin, cos, tan?
A
Use their inverses sin^-1, cos^-1, tan^-1
7
Q
Bearings
A
Directions on a compass (where north points)
8
Q
Angle of depression
A
Angle below the horizon
9
Q
Angle of elevation
A
Angle above the horizon
10
Q
Sine rule
A
Can be used for any triangles (right-angles or non right-angled)
11
Q
Cosine rule
A
**Use when sin rule failed
You need to know two sides, plus the other side / angle
