Answer:
Face B has an area of 28 cm2
Explanation:
Area of a Rectangle
Given a rectangle with dimensions X and Y, the area of the rectangle is calculated as:
A=X*Y
Area of a Triangle
Given a triangle with dimensions X and Y, the area of the triangle is calculated as:
![\displaystyle A=(X*Y)/(2)](https://img.qammunity.org/2021/formulas/mathematics/college/zaq92kiligd8xz96djjyv3lp5jg0whx9xb.png)
We need to find the face of the figure with an area of 28 cm2. A quick look can give us the solution since we only need to find a shape of dimensions 7 and 4. Face B is the only one to have an area of 28 cm2. Let's try them all:
Face A: Rectangle of dimensions 5 cm, 7 cm. Area=5*7=35 cm2. Incorrect
Face B: Rectangle of dimensions 4 cm, 7 cm. Area=4*7=28 cm2. Correct
Face C: Rectangle of dimensions 3 cm, 7 cm. Area=3*7=21 cm2. Incorrect
Face D: Triangle of dimensions 3 cm, 4 cm. Area=3*4/2=6 cm2. Incorrect
Face E: Apparently a triangle congruent to face D. If so, Incorrect
Face B has an area of 28 cm2