Math
posted by Johnny
o is the center of the regular pentagon ABCDE. How many degrees are there in OAB?
Please explain or show work
A.36
B.54
C.72
D.108
E.126

Steve
divide 360 into 5 equal parts. What do you get? 72.
But, that is angle AOB, the vertex of an isosceles triangle. So, each of the base angles (OAB and OBA) is (18072)/2 = 54.
Respond to this Question
Similar Questions

geometry
In the diagram, ABCDE is a regular pentagon with the measure of represented by 2x + 1. If the perimeter of the pentagon is 45, find the value of x. 
math
can someone please answer these questions for me? 
Algebra
Regular pentagon ABCDE is inscribed in circle O. What is the number of degrees in the measure of angle OCE? 
Math
The perimeter of a regular pentagon is 35in. What is the lenght of one side of the pentagon? 
geometry!
ABCDE is a regular pentagon. On the outside of AB, we construct a square ABFG. What is the measure (in degrees) of ∠EAG? 
pentagon...GEOMETRY
ABCDE is a regular pentagon. FAD is an equilateral triangle, such that points F and E are on the same side of line AD. What is the measure (in degrees) of ∠FAB? 
Geometry
ABCDE is a regular pentagon. FAD is an equilateral triangle, such that points F and E are on the same side of line AD. What is the measure (in degrees) of \angle FAB? 
Geometry
I don't understand this can someone please point me in the right direction. The Pentagon pictured below is regular. What is the image of line CA after a rotation of 216 degrees? 
Geometry
Problem: ABCDE$\ is an equilateral pentagon with side length 2 in which angle B= angle E=120 degrees. The area of ABCDE can be expressed in the form square root of x + square root of y for some integers x and y. Find x+y. I don't understand. … 
MATH
A REGULAR PENTAGON ABCDE AND A SQUARE ABFG ARE FORMED ON OPPOSITE SIDE OF AB. FIND ANGLE BCF..