To find the surface area you will need to find the area of all 5 surfaces (faces) on the prism. On a triangular prism there are 2 triangular faces and 3 rectangular faces. All 3 rectangular faces are the same and the 2 triangular faces are also the same.
To find the area of the triangular faces, you will use the formula for finding the area of a triangle:
A = 1/2bh
1/2 x 10 x 8.7
A = 43.5 in^2
To find the area of the rectangular faces, you will use the formula for finding the area of a rectangle:
A = bh
10 x 3
A = 30 in ^2
30 + 30 + 30 + 43.5 + 43.5 = 177
The minimum amount of wrapping paper needed for the gift is 177 square inches.
It is 12 - 2/3 = 18, then solve :)
hope that helps :D
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Since ABCD is a parallelogram, the opposite sides will be parallel and equal,

Consider that AC acts as a transversal to the parallel lines AB and CD, so we can write,

So by the ASA criteria, the triangle AED is congruent to the triangle CEB,
Then the corresponding parts of the triangles will be equal,

Hence Proved.
First of its y-y1 = m(x-x1)
m is the slope, what it is increasing by.
y1 is the y intercept of your pair.
X1 is the x intercept of your coordinate pair, plug them in. If you dont know slope the formula to find it is:
y2-y1/x2-x1