For this case we have the following equation:

Where,
w: The weight of a spring in pounds
E: the energy stored by the spring in joules.
Substituting values we have:

Making the corresponding calculation:
Answer:
the approximate weight of the spring in pounds is:
1. Draw an accurate picture of the triangle in
the coordinate axes, as shown in the attached picture.<span>
<span>2. Circumscribe a rectangle about the triangle, as shown in
the picture. The coordinates of the points M, N, T are easily identifiable as shown in the
picture.</span>
<span>3. The area of the triangle ABC is The area of
the rectangle - Area 1- Area 2- Area 3.</span>
Area 1 = 1/2(3*7)=21/2
Area 2 = 1/2(4*4)=1/2*16=8
<span>Area 3 = 1/2( 3*7)=21/2</span>
<span>Area 1+Area 2+Area 3=21/2+21/2+8=21+8=29 (units squared)</span>
<span>Area rectangle= 7*7=49 (units squared)</span>
<span>Answer: Area of triangle is 20 units squared.</span></span>
If you look at the figure, triangles XVW and ZYW are similar. So, you can use ratio and proportion to solve this problem. Notice that there are tick marks on th other two sides of the bigger triangles. That indicates that the like signs of ticks are equal. For example, that means XZ = ZW and that XW = 2XZ = 2ZW.
24.4/YZ = XW/ZW
24.4/YZ = 2ZW/ZW
24.4/YZ = 2
Solving for YZ,
<em>YZ = 12.2</em>

mutiply the sides together to get a value and subtract the inside area of the frame to find the area.
Frame

Area inside
16*20 = 320
(7x6) + (7x3) = c. this is the answer