Answer:
4 units wide
Step-by-step explanation:
Let the width of the table be 'w'
Given:
Perimeter of the table is, 
The perimeter of the rectangular table is given as the sum of all the sides of the rectangle. The sides include two lengths and two widths.
Length of the table is 8 times longer than its width. Therefore,

Now, perimeter is given as:

Now, plug in 72 for 'P' and solve for 'w'. This gives,

So, the table is 4 units wide.
Answer:
5.0 ft - 5.6 ft
Step-by-step explanation:
Given that the structure is to be made using two 12 foot boards, then we expect the total perimeter to be equal to (2*12)= 24 ft.
Using the angle of elevation, 40° and the width of 8 ft then you can apply the formula for tangent of a triangle where ;
Tan α = opposite side length/adjacent length
Tan 40°= h/8
h= 8 tan 40° = 6.71 ft
Applying the cosine of an angle formula to find the length of the sliding side
Cosine β = adjacent length /hypotenuse
Cosine 40°= 8/ sliding side length
sliding side length = 8/cosine 40° =10.44 ft
Checking the perimeter = 10.44 +8+6.71= 25.15 ft
This is more than the total lengths of the boards, so you need to adjust the height as;
24 - 18.44 = 5.56 ft ,thus the height should be less or equal to 5.56 ft
h≤ 5.6 ft
The most accurate "estimation" for 5+4 is um... 9