What is a number that is between 25 and 50 and the one digit is two less than the tens and is prime

31

This is simple. The tens digit has to be two less than the ones.
The numbers that fit this rule are...
20 31 42 53
Then, they have to be in between 25 and 50.
The numbers that fit this rule are...
31 and 42
Then, i has to be prime
31 is the only one that fits all three 

120m^2

Step-by-step explanation:

Let's start with the bottom. Since the height, base and width are all 4m, we can say that one square = 16 m^2.

There are 5 squares (counting the bottom), and 16 * 5 = 80.

Now the top triangles. We can split the bigger triangle in half. The base is 4m, you can tell from the bottom. To find the area of the triangle, split 4 in half to find the base of the smaller triangles, which equals 2.

Now for the smaller triangles, the base is 2 and the height is 5. We know that to find a triangle's area, you do (b * h)/2, which is (2*5)/2 = 5.

The big triangle is 2 of the small triangles, so you can multiply the smaller triangle's area by 2, which is 5 * 2 = 10.

There are 4 identical triangles at the top-- so 10 * 4 = 40.

80 + 40 = 120.

Hope this helps!