Can someone pls answer these questions thks ok
1 . a cylinder whose diameter is 6 cm and whose height is 4 cm then find its volume
11 . a cube whose edge is 3.5 inches
pls use v=bh for both anyone who answers

OK.  I think we can do that.

' V= b h ' means  " Volume = (area of the base) x (height) "

That can work for both a cylinder and a cube. 
(But the cylinder has to be standing up on one end.)

-- Cylinder:

The base that it's standing on is a circular end.
The area of a circle is  A = π (radius)² .
Radius = 1/2 of the diameter = 1/2 of 6 cm = 3 cm .
Area of the circular base = π (3 cm)² = 9 π cm²
Height of the cylinder = 4 cm
V = b h = (9 π cm²) (4 cm) = 36 π cm³ = 113.1 cm³ (rounded)

-- Cube:

Every edge of the cube is the same length ... 3.5 inches
Every face of the cube is a square.
Area of a square = (side length)²
Area of the base that the cube is sitting on = (3.5 inches)²
Volume of the cube = b h = (3.5 inches)² (3.5 inches)

                                        = (3.5 inches)³ = 42.875 inches³

Your cleary not see the answer is 25