Since they're vertical angles, they're equal in degree measure
since they're equal, we can make the two expressions equal to each other
5a - 1 = 2a + 20
add 1 to both sides
5a = 2a + 21
subtract 2a from both sides
3a = 21
divide both sides by 3a
a = 7
now, plug the answer you found for a into one of the two expressions
5a - 1 becomes (5*7) - 1, which equals 34
to double check that they're equivalent (since they're vertical angles)
2a + 20 becomes (2*7) + 20, which equals 34
both angles are 34 degrees!
We know that : (a - b)(a + b) = a² - b²
We know that : 1 - sin²x = cos²x
We know that : sec²x = 1 + tan²x
Answer:
b
Step-by-step explanation:
polygons is a plane figure that is described by a finite number of straight line segments connected to form a closed polygonal chain or polygonal circuit
Answer:
rational number
Step-by-step explanation:
A rational number can be expressed in the form
, where a and b are integers
- 8 = 
← a rational number
Angles 6 and 8 add up to equal 180, so 2x - 5 + x + 5 = 180. 3x = 180 so x = 60. Angle 3 is alternate interior to angle 6 which is 2(60) - 5 = 115, so angle 3 is also 115
