Hello students, today we are going to see about plus 1 physics measurement of basic quantities in the topic of user soft triangulation method. It is used for measuring larger distances such as the height of the tree, distance of moon and a planet from earth. And this is the definition of the triangulation method and now we are going to see about the explanation. As you can see in the figure, AB is the tree and its height is measured as H. So, AB equal to H and C is the point on the ground and C is the point of observation. And the distance between the base of the tree that is B and the point of observation C, BC equal to X is the distance and now the hypotenuse is drawn AC and the angle between ACB is taken as Teta which is the angular elevation of the top of the tree. As we already know, Tanteta equal to opposite side and adjacent side. The reason why we are taking a Tanteta is we have two values that is the opposite side value and the adjacent side value. And now we are going to calculate the height of the tree. In the Tanteta equal to AB by BC according to the figure. So Tanteta equal to AB equal to H and BC equal to X. So Tanteta equal to H by X. Now we are cross-producing it, we will get H equal to X into Tanteta. So by knowing the value of X and Teta, we can conclude the value of H. Now we are going to see one example and it is from our textbook. Like this in the page number 13, X. 1.1. The question is from a point and the ground, the top of the tree is seen to have an angle of elevation of 60 degree. The distance between the tree and the point is 50 meter, calculate the height of the tree. Now we are going to write the given data separately. So the Teta equal to 60 degree. The angle of elevation is 60 degree which we calculated in knit tan value and X is the distance between B and the C is 50 meter. Now we have to calculate the H by using our formula, H equal to X Tanteta which we got from Tanteta equal to H by X. Now X is 50 meter and Teta is 50. The value of tan 60 is square root of 3 equals 1.732. So 50 into 1.732 gives us 86.6 meter which is the height of the tree and that is it. But we guys understood it and if you have any doubts, ask us in the comments section. We are ready to answer your questions. Thank you.