NCERT Solutions for Class 9 Maths Chapter 8 Exercise 8.1

What to Study in Class 9 Maths Chapter 8

We have studied many properties of a triangle so far in the mathematics chapters of classes 9 and 6, and we know that by adding three non-collinear points in pairs, the figure thus obtained is a triangle. We mark the four points and see what we get by matching them in couples in order. Note that if all the ends meet together (on the same line), we get only one segment; if three of the four points match, we get a triangle, and if four of them If three points do not meet each other, then we get a closed figure with four. Sides. Thus a shape formed by the union of four points in a sequence is called a quadrilateral. In Mathematics Class 9, Chapter 8, we will consider only different types of quadrilaterals.

Quadrilateral in daily life

A quadrilateral has four sides, four angles, and four corners. In quadrilateral ABCD, AB, BC, CD, and DA are four arms; A, B, C, and D are four corners, and A, B, C, and D are four angles. Now join the opposite corner with C and B with D and AC. AC and BD are two diagonals of the quadrilateral ABCD. In Chapter 8 of the Ninth Mathematics, we will study more about the different quadrilaterals, properties, and parallelograms. We may wonder why we should explore quadrilaterals (or parallel quadrilaterals). If we look around us, we will find many objects with the shape of a quadrilateral: floors, walls, ceilings, your classroom windows, blackboards, each face of the duster, each page of your book, part of our study: table, and many other things.

Different Kinds of Quadrilaterals

Sometimes, the objects we look around, maybe in the shape of a rectangle. Chapter 8 of Class 9 Maths will study more about the quadrilateral, especially the parallelogram. A rectangle is also a parallel quadrilateral, and all the properties of a rectangle are valid for a rectangle. Let us now recall the property of the sum of the angles of a quadrilateral. The sum of the angles of a quadrilateral is 360. The fact can be verified by drawing a diagonal and dividing the quadrilateral into two triangles.

Some essential facts about a square, a rectangle, and a rhombus are all parallelograms.

1. A square is a rectangle and also a rhombus.
2. A parallelogram is a trapezium.
3. A kite is not a parallel quadrilateral.
4. A trapezium is not a parallel quadrilateral (since only one pair of opposite sides is in parallel, and we need both pairs to be parallel in a parallel quadrilateral).
5. A rectangle or a mausoleum is not a square.