Explanation:
I will take long to answer this so i will give you the key to answering it.
Basically, since you know the sum of all the angles of a triangle equal 180, all you have to do is use 180 and subtract the numbers alredy there together to get the missing amount.
For example, to find out the answer to A, you already know two of the degree measurements which are 72 and 68. Now, subtract them with 180.
72+68=140
180-140=40
So, therefore, A equals 40 degrees.
I will give you one more example.
If you want to find the measurements of the angles B and C, the same process will happen. The only thing that is different is that only one known measurement is provided which is 36.5 but not so fast, they gave you a hint. That square above B. That means B is a right angle. So we got one measurement in the triangle, B is 90 degrees. Alright now continue like before.
90+36.5=126.5
180-126.5=53.5
Hope this helps.