The answer is 40°
i will tell you how,
Total angle sum of any triangle is 180°
∠A + ∠B + ∠E = 180°
70° + 80° + ∠E = 180°
solve for ∠E
∠E = 30°
Now solve use ∠BDE,
∠B + ∠D + ∠E = 180°
20° + 90° + 30° + x = 180° (in triangle DEB, ∠E = 30 + x ) (∠D is 90°)
solve for x
there fore, x = 40°
The mean is the average number meaning that it is all the numbers in a set added together and divided by how many number are in the set. In this case there are 4 numbers (16, 3, whatever number x is, and 5). So, to find out what x is, first you multiple 4 by the known mean which is 9.
4 x 9 = 36
Then you simply subtract 36 from all the known numbers to find x.
36 - 16 - 5 - 3 = 12
So x = 12
Answer:
10
Step-by-step explanation:
it's kinda hard to explain
Since it's isosceles, ∠ABC = (180-30) / 2 = 75
