Geometry Flashcards
What are supplementary angles?
Sum of angles equal 180deg
What are complementary angles?
Sum of angles equal 90deg
A cyclic quadrilateral (quad with vertices on circle circumference) have what property?
Opposite angles are supplementary (sum equals 180deg)
For a regular polygon, what are the equations to find the:
1. Interior Angles
2. Exterior Angles
- IA = (n-2)/2 x 180deg
- EA = 360/n
For any polygon, what are the equations to find the sum of the:
1. Interior Angles
2. Exterior Angles
- Sum(IA) = (n-2) x 180deg
- Sum(EA) = 360
What are the two equation forms of a linear line in coordinate geometry?
- Standard: ax + by +c = 0
- Slope/Intercept: y = mx +c
In coordinate geometry, when a linear equation has 1 variable, it has what relationship to the axes?
It is parallel to one of the axes
How do you calculate the midpoint between 2 coordinates?
MP = ( (X1+ X1)/2, (Y1 + Y1)/2)
How do you find the gradient between 2 points?
(y2 - y1) / (x2 - x1)
How do you calculate the distance of coordinates from the origin?
Distance = sqrt((x^2) + (y^2))
In coordinate geometry, how do you calculate the distance between two points?
sqrt( (x1-x2)^2 + (y1-y2)^2 )
If a triangle on a coordinate plane has no sides parallel to the axis, how do you find the area?
Area under the graph - Area not included
In a coordinate plane how do you know if 2 lines are perpendicular?
Product of gradients =1
IOW gradients are reciprocal
OR
(a1a2) = (b1b2)
What is the area of a trapezium?
A = (1/2)(a+b)h
In a coordinate plane how do you know if 2 lines intersect?
(a1/a2) =/= (b1/b2)
In a coordinate plane how do you know if 2 lines are coincident?
(a1/a2) = (b1/b2) = (c1/c2)
In a coordinate plane how do you know if 2 lines are parallel?
(a1/a2) = (b1/b2) =/= (c1/c2)
For a cuboid how do you find:
1. Body Diagonal
2. Face Diagonal
3. Minimum surface distance?
- db = sqrt(l^2 + w^2 + h^2)
- df = sqrt(l^2 + w^2)
- Min SD = sqrt(l^2 + (w + h)^2)