Answer:
The surface area is equal to 
Step-by-step explanation:
The surface area of the triangular pyramid is equal to the area of its four triangular faces
so
In this problem
![SA=4[\frac{1}{2}(b)(h)]](https://tex.z-dn.net/?f=SA%3D4%5B%5Cfrac%7B1%7D%7B2%7D%28b%29%28h%29%5D)
we have


substitute the values
![SA=4[\frac{1}{2}(15)(13)]=390\ in^{2}](https://tex.z-dn.net/?f=SA%3D4%5B%5Cfrac%7B1%7D%7B2%7D%2815%29%2813%29%5D%3D390%5C%20in%5E%7B2%7D)
All the prime numbers betwemn 20 and 30 are 23 and 29
Answer:
-12/5
Step-by-step explanation:
-4 * 9 = -36 (numerator)
3 * 5 = 15 (denominator)
Take 3 out of both to simplify.
-36/3 = -12
15/3 = 5
Final Answer:
-12/5
Let
denote the number of seats in the
-th row.
is arithmetic, so

for some constant
.
We're told
and
, so that



and so on up to

The pattern continues:


and so on up to

Lets say N as cells
On monday N = 3
Multiply means that on tuesday is 9 cells and
Wednesday will 27 cells
Therefore N on wednesday is
No. of cells = 9n