Answer:
EF = 11
Step-by-step explanation:
AD/DE = 3
Therefore, DC/3 = EF
33/3 = 11
First find the mean (sum divided by number of values)
4+5+8+10+15=42
42/5=8.4
Then find the difference between each of the numbers and the mean.
4.4, 3.4, 0.4, 1.6, 6.6
Then find the mean of those values.
4.4+3.4+0.4+1.6+6.6=16.4
16.4/5=3.28
Final answer: 3.28
Answer:
x = 130/3
Step-by-step explanation:
Given
5x - 80 = 2x + 50
Transpose
5x - 2x = 50 + 80
3x = 130
x = 130/3
Answer:

Step-by-step explanation:
(y+5)(y+5)x3/2=4
Y(y+5)+5(y+5) x 3/2=4





Answer:
319
Step-by-step explanation:
So, to find the surface area, first we find the base area, which is: 11 x 11 = 121
Then, we have to find the area of the other faces. Since each face is a triangle, we can use the formula A = 1/2 x b x h.
So,
b = 11
h = 9
1/2 x 11 x 9 = 49.5
The, we multiply by 4, the number of sides: 49.5 x 4 = 198
Then, we add the 2, values: 121 + 198,
Which gives us: 319.
Hope this helped!