Home | | Maths 10th Std | Points to Remember

# Points to Remember

Mathematics : Coordinate Geometry: Points to Remember: Equation, Formulas, forms

Points to Remember

·           The area of a triangle formed by the points (x1 , y1 ) , (x2 , y2 ) and (x3 , y3 ) is 1/2 { (x1y2 + x2y3 + x3 y1) (x2y1 + x3y2 + x1y3) } sq.units

·           Three points A(x1,y1),B(x2,y2) and C(x3,y3) are collinear if and only if

(i) area of ΔABC = 0 or x1y2 + x2y3 + x3y1 = x2y1 + x3y2 + x1y3

(ii) slope of AB = slope of BC or slope of AC

·           The area of a quadrilateral formed by the four points  (x1 , y1 ) , (x2 , y2 ), (x3 , y3 ) and (x4 , y4 )is 1/2 { (x1y2 + x2y3 + x3 y4+ x4 y1) (x2y1 + x3y2 + x4y3+ x1y4) } sq.units

·           If a line makes an angle θ with the positive direction of X axis, then its slope m = tanθ.

·           If A(x1,y1), B(x2,y2) are two distinct points then the slope of AB is (y2 - y1) / (x2 - x1).

·           Slope of line ax+by+c= 0 is m =  − a/b.

Equation of straight line in various forms ·           Two straight lines are parallel if and only if their slopes are equal.

Two straight lines with well defined slopes m1, m2 are perpendicular if and only if m1×m2 = −1.

Tags : Coordinate Geometry | Mathematics , 10th Mathematics : UNIT 5 : Coordinate Geometry
Study Material, Lecturing Notes, Assignment, Reference, Wiki description explanation, brief detail
10th Mathematics : UNIT 5 : Coordinate Geometry : Points to Remember | Coordinate Geometry | Mathematics