Answer: 
Step-by-step explanation:
Equilateral triangle has equal sides, let the side be
, then the perimeter is 
Therefore:



To find the altitude , we will apply Pythagoras theorem , that is

Therefore:



take the square root of both sides

Answer:
20cm^2
Step-by-step explanation:
0.5x(7+3)x4=20cm^2
Haha number one is 3 and two is 2
The line should go from (0,0) to (7,3.5)
The equation is Y = X(0.5)
Well a perfect square looks like this:
6 x 6
2 x 2
So the number 72 is between the PRODUCT of two perfect squares such as those.
One product has to be above 72, and the other below it.
So lets multiply.
8 x 8 = 64
9 x 9 = 81
Oh look at that, 72 is between 64 and 81.