To answer question 12, you first need to know the definition of a <em>prism</em> and a<em> pyramid.
</em>A <em>pyramid </em> is a 3-D structure with one base, whose outer faces are made of triangles, and meet at a single point at the top.
A <em>prism</em> is any 3-D shape with a base of any number of sides, another base with the same amount of sides, and faces joining the two together on every side of the bases.
12.
Shape A is a <em>pyramid</em>, because it has one base, and all the faces join together in at one point.
Shape B is a <em>prism</em>, because it has two bases, and faces joining every side of the bases.
Shape C is a <em>prism.</em>
Shape D is a <em>pyramid.
</em>For #13, you have to know the definition of a cube to figure out the math of how many cubes there are.
A cube is a 3-D shape with six sides, all made up of squares of the same size.
The box has a volume of 120 cubic inches, and each cube is 1 inch. Since every side of a cube is equal, a 1-inch cube is one cubic inch.
This means that a box with a volume of 120 cubic inches will fit 120 of the 1 inch cubes.
1 layer of the cubes, in the diagram, is 8 cubes by 3 cubes, or 24 cubes total.
To find the number of layers needed to fill the box, you divide 120 by 24.
120 ÷ 24 = 5
The answer to #13 is 5 layers.
1/9 + 1/2 = 1/x
Let x = length of time it will take both hoses to work together
Multiply both sides by 18x.
2x + 9x = 18
10x = 18
x = 18/10
x = 9/5
x = 1.8 hours
In other words, if both hoses work together, the pool can be filled in 1 hour and 48 minutes.
Alright, the zeroes are where it intersects with the X-axis so...
4) -15 and 10
5) 6 and 18
6) -5 and 0
7) -20 and -8
8) 2 and 10
9) -21 and 14
Hope I was able to help you :)
The answer to the second one is 243/2 but I'm not 100% positive
