An architect is making a deck in the shape below, where 1 unit = 1 foot. If one quart of deck stain can cover 8 square feet, how many quarts need purchased to stain the deck once?

5 quarts

Step-by-step explanation:

I think your question is missed of key information, allow me to add in and hope it will fit the original one.  

Please have a look at the attached photo.  

My

Given the information:

We need to find the area of the shape by breaking down it into 2 triangles and 1 rectangle.

=> the area of the rectangle : length*width = 7*4 =28 square units

=>  the area of the triangles using : 1/2*length *width = 1/2*4*3 = 6 square units

Hence, the total area is: 28 + 6 + 6 = 40 square units

=> the number of  quarts need purchased to stain the deck once:

= 40/8 = 5 quarts

Hope it will find you well.

ab will be equal to