class 10 mathematics [triangles]

Question: The sides AB, BC, CA of a triangle ABC have 3, 4 and 5 interior points respectively on them. Find the number of triangles that can be drawn using these points as vertices. Answer: The points 3+4+5=12 points lie in a plane. To construct a triangle,..

We have already learnt in the previous class that the area of triangle whose vertices are (x 1 , y 1 ), (x 2 , y 2 ), (x 3 , y 3 ) is given by Hence area of a triangle having vertices at (x 1 , y 1 ), (x 2 , y 2 ) and (x 3 , y 3 ) is given by..

Question: From 12 books, in how many ways can 5 be chosen i. to surely include a particular book ii. never to include a particular book iii. to have no restrictions at all? Answer: i. To include a particular book, one particular book has already been chosen. We have to select 4 books fr..

Number of ways of filling hundred's place = 2 Number of ways of filling ten's place = 2 Number of ways of filling unit's place = 2 By the fundamental principle of counting, the total number of numbers = 2 x 2 x 2 =..

Now we shall discuss the use of determinants in finding the area of a triangle and in the solution of simultaneous equation..

Question: Find the number of triangles that can be drawn through 12 distinct points, no three of which are collinear. Answer: To draw a triangle, we require three non-collinear points. Hence, the number of triangles that can be drawn is ..

Application of Determinants, Area of a Triangle, Cramer's rule for the solution of a system of equations in 2 variables, Consistency of a system of linear equation. Application of Matrices, Homogeneous Equations (Constant = 0), Non Homogenous Equations (Solution by the Matrix..

Conclusion - We have seen the application of matrices and determinants in solving system of linear equation with three unknown variables. Matrices and determinants are also widely used in solving large system of linear equation. Some of these methods are Gauss-elimination method, Gauss-Jordan metho..

Question: From a class of 12 boys and 10 girls, 10 students are to be chosen for a competition, including atleast 4 boys and 4 girls. 2 girls who won prizes last year should be included. In how many ways the selection can be made? Answer: There are 12 boys ..

Question: Answer: = 5 + 10 + 10 + 5 + 1 = 31 = RH..