Unit 11 volume and surface area homework 2 answer key

Video Transcript

okay for the first one the surface area Think of having two rectangles that are the left which is an eight x 12 and right side. They're congruent eight x 12. Then you have two that are congruent top and bottom. Those are two rectangles that are eight x 17 each. And then the front and back would be two rectangles that are 17 by 12 each. And so you were there um figure all this out with the calculator two times 8 times 12 plus two times eight by 17 Plus two rectangles that were 17 x 12. And that comes out to 872 square inches. Okay, the total surface area in number two we've got two circles, circles are pi times the radius squared. And then that takes care of again the two circles. And then we have a really a rectangle. If you were to think that there's like a label and you unwrapped it, you've got a rectangle. Who's length would be the circumference which is two pi r or pi times the diameter Which would be 28 pi because the diameter would be 28 And then this would be 29. So 29 times 28 pi would be the rectangular part. Again to understand the concept, we've got two times the circle bases plus A rectangle, that's 29 By 28 pi to the nearest 100 so two times hi times r squared plus 29 times 28 pi So 37 82.48. Okay to the triangular prism. We've got two triangles. The area of a try. Each triangle is one half times its base which is 11 and its height, Which would be 4.3. Mhm. And then we've got three rectangles. We've got a This would be three x 8. The one on the right would be a three x 6. And then to that we'd add The back rectangle, which would be three x 11 mm hmm. Okay, so two times yeah, 1/2 times 11 times 4.3 plus one rectangle. That is three x 8 Plus a rectangle. That's three x 6. And plus another rectangle, That is three x 11. That's 1 22.3. And finally we have a trapezoidal prism. The surface area would be equal to let's let's head out the trapezoid right away. These trapezoid, we've got two of them to calculate the area of the traps which is one half times the sum of the bases. The basis would be 19 and five. You add those together And multiplied by the height, which is 12.1 to this. We would add We've got the two trapezoid and now we've got four rectangles. The bottom would be a five x 8 rectangle. Okay, and the one on the right would be a 14 by eight, which is the same. We actually got two of those, So to 14 x eight rectangles. And then we've got the top rectangle which would be an eight x 19. Alright, so We've got two trapezoid each, trapezoid is 1/2 Times of some of the bases, 19 and five times Its height of 12.1. That's the two trapezoid to those trapezoid is we add a bottom base, which is a five x 8 rectangle. We've got two rectangles on the left and right sides that are 14 by eight, and we've got the rectangle top, which is eight x 19 rectangle 706.4.

HW 8

posted May 2, 2013, 9:55 AM by Jessica Hexsel

See both attached docs for front and back of worksheet.

HW 10

posted May 2, 2013, 9:43 AM by Jessica Hexsel   [ updated May 2, 2013, 9:56 AM ]

HW 6

posted Apr 17, 2013, 3:38 PM by Unknown user   [ updated Apr 18, 2013, 12:50 PM ]

HW 5

posted Apr 17, 2013, 3:29 PM by Unknown user

Answer key attached below.  Check your answers!

HW 4

posted Apr 15, 2013, 6:11 PM by Unknown user

Check your answers on the key below!

HW 1 Sample

posted Apr 10, 2013, 7:35 PM by Unknown user

This is an example of a student's dichotomous key (certainly not the only way to complete this!)