SA of triangular prism help please

B. 74

Step-by-step explanation:

The surface area is just the area of the two triangular bases plus the area of the three rectangular sides.

Area of a triangle = (1/2)bh, where b is the base and h is the height. Here, b = 4 and h = 3.5. So: (1/2) * 4 * 3.5 = 7. However, we have two triangles, so we multiply 7 by 2: 7 * 2 = 14.

Area of a rectangle = bh, where b is the base and h is the height. Here, b = 5 and h = 4. So: 5 * 4 = 20. However, there are three rectangles, so we multiply 20 by 3: 20 * 3 = 60.

Now, we just add these together: 14 + 60 = 74.

Thus, the answer is B.

Hope this helps!

2. 74 cm²

Step-by-step explanation:

3 rectangles + 2 triangles

3(4×5) + 2(½×4×3.5)

60 + 14

74 cm²

3. parallelogram

step-by-step explanation:

we turn each of our sides into direction vectors

ab=b-a=(3 - 7, 1 - 0) = (-4, 1)

bc=c-b=(1,6)

cd=d-c=(4,-1)

da=a-d=(-1,-6)

we see how the opposite sides have negated direction vectors; this is characteristic of a parallelogram.   we have congruent sides ab=cd and bc=da with unequal lengths because 1^2+6^2 is different from (-4)^2+1^2.   so it's not a square or a rhombus.  

we check the dot product of direction vectors of adjacent sides.   we have

ab dot bc = -4(1) + 1(6) = 2

that's not zero so the sides are not perpendicular.   we've ruled out rectangle.

the direction vectors indicate two pairs of congruent parallel sides, so we choose parallelogram over trapezoid.

b) 1/3 * 1/5

step-by-step explanation:

each smallest part is 1/15 since the written one is 1/5 and it's divided by 3 equal parts. (1/5 )/3 = 1/15 = 1/3 * 1/5