00:01
So this is the given question.
00:02
We are asked to find all the missing sides and angles of this triangle.
00:07
Okay? let us see how we can do this.
00:09
Now i am drawing this triangle again.
00:13
Since it is oriented like this, now i am drawing the same triangle like this.
00:21
I will name them wait.
00:23
See here at c we have right angle.
00:25
Since it is right angle, this point is c.
00:28
Here we have right angle.
00:29
Okay, this point is a and this point is b.
00:34
Let us take, i have just rotated the triangle in this direction and this is 70 degrees.
00:40
At b we have 70 degrees and the length of the side a, b is 7.
00:47
Now let us consider this angle as a.
00:53
Suppose consider this angle as theta.
00:56
Okay, now you have one basic formula, one basic statement that is sum of all angles in a triangle sum of all angles in a triangle equal to 180 degrees okay from this statement the sum of all angles is theta plus 70 plus this is right angle right angle means 90 degrees okay so plus 90 degrees equal to 180 degrees therefore theta equal to 180 minus 70 minus 90 degrees so theta will be equal to 20 degrees so we have found the value now let us try to find the remaining sides suppose consider this side cb as a and side ac as v now we have to find both sides cb and ac let us not take any value now since this is a right angle triangle okay this is a right angle triangle and this is hypotenuse the side opposite to 90 degrees since this is 90 degrees this side opposite to 90 degrees is this one so this is hypotenuse its length is 7 now from a basic technometric ratios okay we can write sign 70 okay sign 70 as you know that sine theta equal to opposite side by hypotenuse i am writing opp means opposite side hipp means hypotenuse.
02:42
Okay? this side opposite to 70 degrees is this one.
02:47
So that is nothing but ac.
02:50
Evertenture is nothing but a, b...