Use euler’s formula to find the number of vertices in a polyhedron with four triangular faces.

Step-by-step explanation:

we know that

The Euler's formula state that, the number of vertices, minus the number of edges, plus the number of faces, is equal to two

Let

V----> the number of vertices

E------> the number of edges

F------> the number of faces

In this problem we have

substitute in the formula and solve for V

see the attached figure to better understand the problem

b. 1.25 hr

step-by-step explanation:

if you have a constant speed of 60 mph, then you have a ratio between 60 mi. to 1 hr. dividing both sides by 60 we get the ratio

1 mi. to

then mult. both sides by 75 we get the ratio

75 mi. to

simplifying we get

75 mi. to

or 1.25 hr.