Four triangles are formed by joining the mid points of three sides of a triangle.

A regular polygon: A polygon having all sides of equal length and the interior angles of equal size is known as regular polygon. (i) 3 sides Polygon having three sides is called...

(i) 9 sides Solution: Since, 9 sides of a polygon has nine angles And we know that sum of exterior angles of a polygon = 360⁰ So, 9 exterior angles = 360° Or, 1 exterior...

(a) Rhombus and square have sides of equal length. (b) Square and rectangle have four right angles.

(i) No, a polyhedron cannot have 3 triangles for its faces. (ii) Yes, a polyhedron can have four triangles which is known as pyramid on triangular base. (iii) Yes, a polyhedron has...

Let OA be the line joining the origin, O (0, 0, 0), and the point, A (2, 1, 1). Also, let BC be the line joining the points, B (3, 5,...

Since the perimeters and two sides are proportional Therefore, the third side is proportional to the corresponding third side. i.e., The two triangles will be similar by SSS criterion.

A' is the set of all equilateral triangles.

(d) Area of the quadrilateral whose side and one diagonal are given can be calculated by dividing the quadrilateral into two triangles and using the Heron's formula.

(b) Maximum number of triangles can be formed by selecting 3, 4 or 5 points out of 6 at a time.  So, maximum no. of triangles = 6C3 + 6C4 +...

Draw ID ⊥ AC. Then ID = r, the inradius of ΔABC. Observe EF || BC and hence ∠AEF = ∠ABC = 900. Hence ∠AIF = 90º. Therefore ID2 = FD x DA. If...