What are the surface areas of those ?

7) . 8)

Step-by-step explanation:

7)

Here we have two different types of faces.Bottom face and side faces which are equivalent.

To calculate the area of a trinagle we have the formula of area to be

where a is the height of the triangle and b is the base of the triangle.

here let us first calculate the area of the bottom face,

now for the top faces which are similar, areas would be

Hence the total area is

8)

As we have seen in the above question area for a traingle would be

and for rectangle would be where l and b are the lengths and breaths of the rectangle.

Area of traingles would be ,

Area of rectangles would be,

Hence the total area is

25 questions , because they start with 100.  

350-100=250 .  

. 250/10=25

step-by-step explanation:

first take off 100, then what x 10 = 250? that is your answer. (25)