 Hello friends, welcome to the session. I am Arka. Let's discuss the triangles. Our given question is in figure 6.35 triangle ODC is similar to triangle OBA and angle BOC equal to 125 degree and angle CDO equal to 70 degree. Find angle BOC, DCO and OAB. We can see from the figure that angle BOC is 125 degree and angle CDO is 70 degree. Now let's start with the solution. We can see from the figure that BD is a line and OC is a ray on it. So OC, so using this property we can say that angle BOC BOC plus BOC equal to 180 degree that is my linear pair equal to 180 degree linear pair. Now we know that angle BOC is 125 degree so it can be written as 125 degree plus we have to find angle BOC equal to 180 degree. Now angle DOC equal to 180 degree minus 125 degree. This implies angle DOC equal to 55 degree. Therefore we get the angle DOC that is 55 degree. Now again we can see in triangle COD using an angle sim property that is sum of 3 angles 180 degree we will use it here. Angle CDO plus angle DOC plus angle DCO equal to 180 degree by angle sum property. This implies we know that angle CDO is 70 degree 70 degree plus DOC is 55 degree plus we are having no idea of angle DCO as we have to calculate angle DCO. So it will be written as angle DCO equal to 180 degree. So this implies angle DCO equal to 180 degree minus 70 degree minus 55 degree. This implies angle DCO equal to 180 degree minus 125 degree. Therefore angle DCO equal to 55 degree. So we get angle DCO as 55 degree. Now we have given in the question that triangle ODC is similar to triangle OBA it is given this implies angle OVC is equal to angle OBA equal to 70 degree since angle ODC is 70 degree. Now we see that triangle ODC is similar to triangle OBA. Therefore angle ODC is equal to angle OVA. DCO is equal to angle OAB equal to 55 degree. And according to the question we have to find the value of angle OAB. Now we get this because angle DCO equal to 55 degree. This implies angle DOC equal to angle AOV equal to 55 degree as angle DOC equal to 55 degree. We can see from the figure that angle DOC is 55 degree. Therefore angle AOV will also be 55 degree since the two given triangles are similar to each other. Therefore we get that angle OAB equal to 55 degree. Therefore required angles are 55 degree, 55 degree, 55 degree. Hope you understood the solution and enjoyed the session. Goodbye and take care.