Draw two lines `bar(AB)` and `bar(CD)` such that they intersect at point 'O' .Trace the figure given below on a tracing papier. Place the traced figure over the figure given below and rotate it such that `/_DOB` coincides `/_COA`,Observe the angles `/_AOD` and `/_BOC` also `/_COA` and `/_DOB`.You will notice that `/_AOD=/_BOC` and `/_CDA=/_DOB`

In the given figure lines bar(AB) and bar(CD ) intersect at O. If angleAOC+ angleBOE= 70^(@) and angleBOD = 40^(@) , find angleBOE and reflex angleCOE .

In the given figure three lines bar(AB) , bar(CD) and bar(EF) intersecting at O. Find the values of x, y and z it is being given that x : y : z = 2 : 3 : 5

The common point of the tangent and the circle is called the point of contact and the tangents is said to touch the circle at the common point. Observe the tangents to the circle in the figures given below. How many tangents can you obtain to the circle.in all?See the points of contact. Draw radii from the points of contact. Do you see any thing special about the angle between the tangents and radii at the points of contact. All appear to be perpendicular to the corresponding tangents. How many tangents can you draw to a circle at a point?

The common point of the tangent and the circle is called the point of contact and the tangents is said to touch the circle at the common point. Observe the tangents to the circle in the figures given below. How many tangents can you obtain to the circle.in all?See the points of contact. Draw radii from the points of contact. Do you see any thing special about the angle between the tangents and radii at the points of contact. All appear to be perpendicular to the corresponding tangents. How many tangents can you obtain to the circle in all?

The common point of the tangent and the circle is called the point of contact and the tangents is said to touch the circle at the common point. Observe the tangents to the circle in the figures given below. How many tangents can you obtain to the circle.in all?See the points of contact. Draw radii from the points of contact. Do you see any thing special about the angle between the tangents and radii at the points of contact. All appear to be perpendicular to the corresponding tangents. Draw radii from the points of contact. Do you see any thing special about the angle between the tangents and radii at the points of contact. All appear to be perpendicular to the corresponding tangents.

Draw a triangle ABC and mark the midpoints E and F of two sides of triangle. bar(AB) and bar(AC) respectively. Join the point E and F as shown in the figure. Measure EF and the third side BC of the triangle. Also measure angleAEF and angleABC . We find angleAEF = angleABC and bar(EF)=(1)/(2)bar(BC) As these are corresponding angles made by the transversal AB with lines EF and BC, we say EF"||"BC.