Hi,
Sorry. I am having a very difficult time with surface area. I tried to work the last two out but I am not sure if they are correct or not*. The other three I can't seem to figure out at all. Please help! Thank you!
*(sorry for my crappy writing)
+4622 Last one: There are 6 faces, I think, wait, yes! So, the area of the first face, 2nd face: 2(20*10)=2(200)=400yd^2
Area of the 3rd face, 4th face: 2(20*20)=2(400)=800yd^2
Ares of the 5th face, and 6th face: 2(20*10)=2*200=400yd^2.
Thus, the surafce area is 400+400+800=1600yd^2. You're correct!
+4622 5th one: Two trapezoids! No! Area of a trapezoid: 2(51.85)- use the formula=103.7 mi^2.
Rectangles: 2(14*7)=196 mi^2
Bottom rectangle: 5*14=70 mi^2
Top rectangle: 168 mi^2
So, 103.7+196+70+168=537.7? I might be wrong.
+4622 1st one: Base, which is a rectangle: 18*20=360mi^2
2*(1/2*20*14.2) and 2*(1/2*18*14.9)=20*14.2+18*14.9=284+268.2=552.2mi^2
So, 360mi^2+552.2mi^2=912.2mi^2.
+130071 Third one (on top right)
We have a triangular pyramid
The sides are 3 congruent triangles with bases of 9 cm and heights of 19.2 cm
So...their total area is (3)(1/2) (9) (19.2) = 259.2 cm^2
The base is a triangle with a base of 9cm and a height of 7.8 cm
Its area is (1/2) (9)(7.8) = 35.1 cm^2
So.....the total surface area is 259.2 + 35.1 = 294.3 cm^2
+130071 Middle one at top
We have a triangular prism
The top/bottom are congruent triangles with base = 15 in and height of 7.7 in
So the total area of top/bottom is 15 * 7.7 = 115.5 in^2
The sides are rectangles with height of 8 in and widths of ( 15,15 and 8 in)
So the side area is 8 [ 15 + 15 + 8 ] = 8 [ 38 ] = 304 in^2
So..the total surface area is 115.5 + 304 = 419.5 in^2
