All SAT II Math II Resources
Example Questions
Example Question #2 : Faces, Face Area, And Vertices
A regular octahedron has eight congruent faces, each of which is an equilateral triangle.
The total surface area of a given regular octahedron is 400 square centimeters. To the nearest tenth of a centimeter, what is the length of each edge?
The total surface area of the octahedron is 400 square centimeters; since the octahedron comprises eight congruent faces, each has area square centimeters.
The area of an equilateral triangle is given by the formula
Set and solve for :
centimeters.
Example Question #1 : Faces, Face Area, And Vertices
A regular icosahedron has twenty congruent faces, each of which is an equilateral triangle.
A given regular icosahedron has edges of length four inches. Give the total surface area of the icosahedron.
The area of an equilateral triangle is given by the formula
Since there are twenty equilateral triangles that comprise the surface of the icosahedron, the total surface area is
Substitute :
square inches.
Example Question #31 : 3 Dimensional Geometry
How many faces does a polyhedron with nine vertices and sixteen edges have?
By Euler's Formula, the relationship between the number of vertices , the number of faces , and the number of edges of a polyhedron is
Set and and solve for :
The polyhedron has nine faces.
Example Question #3 : Faces, Face Area, And Vertices
How many edges does a polyhedron with eight vertices and twelve faces have?
Insufficient information is given to answer the question.
By Euler's Formula, the relationship between the number of vertices , the number of faces , and the number of edges of a polyhedron is
Set and and solve for :
The polyhedron has eighteen edges.
Example Question #5 : Faces, Face Area, And Vertices
How many faces does a polyhedron with ten vertices and fifteen edges have?
Insufficient information is given to answer the question.
By Euler's Formula, the relationship between the number of vertices , the number of faces , and the number of edges of a polyhedron is
Set and and solve for :
The polyhedron has seven faces.
Example Question #6 : Faces, Face Area, And Vertices
How many faces does a polyhedron with ten vertices and sixteen edges have?
By Euler's Formula, the relationship between the number of vertices , the number of faces , and the number of edges of a polyhedron is
Set and and solve for :
The polyhedron has eight faces.
Example Question #4 : Faces, Face Area, And Vertices
A convex polyhedron with eighteen faces and forty edges has how many vertices?
The number of vertices, edges, and faces of a convex polygon——are related by the Euler's formula:
Therefore, set and solve for :
The polyhedron has twenty-four faces.
Example Question #5 : Faces, Face Area, And Vertices
How many edges does a polyhedron with fourteen vertices and five faces have?
By Euler's Formula, the relationship between the number of vertices , the number of faces , and the number of edges of a polyhedron is
.
Set and and solve for :
The polyhedron has seventeen edges.
Example Question #1 : 3 Dimensional Axes And Coordinates
Which of the following numbers comes closest to the length of line segment in three-dimensional coordinate space whose endpoints are the origin and the point ?
Use the three-dimensional version of the distance formula:
The closest of the five choices is 7.
Example Question #2 : 3 Dimensional Axes And Coordinates
A line segment in three-dimensional space has midpoint ; has midpoint .
has Cartesian coordinates ; has Cartesian coordinates . Give the -coordinate of .
The midpoint formula for the -coordinate
will be applied twice, once to find the -coordinate of , then again to find that of .
First, set , the -coordinate of , and , the -coordinate of , and solve for , the -coordinate of :
Now, set , the -coordinate of , and , the -coordinate of , and solve for , the -coordinate of :