Answer:
83.5 degrees
Step-by-step explanation:
first, find x:
x+5x-13+4x=180
10x=193
x=19.3
Then, substitute that value for c:
5*19.3-13
=83.5 degrees
Circumference of a circle - derivation
This page describes how to derive the formula for the circumference of a circle.
Recall that the definition of pi (π) is the circumference c of any circle divided by its diameter d. Put as an equation, pi is defined as
π
=
c
d
Rearranging this to solve for c we get
c
=
π
d
The diameter of a circle is twice its radius, so substituting 2r for d
c
=
2
π
r
If you know the area
Recall that the area of a circle is given by
area
=
π
r
2
Solving this for r
r
2
=
a
π
So
r
=
√
a
π
The circumference c of a circle is
c
=
2
π
r
Answer:
θ ≈ 17.1°
Step-by-step explanation:
Using the tangent ratio in the right triangle
tan θ = 
= 
= 
, then
θ = 
( ) ≈ 17.1° ( to the nearest tenth )
It's would be plus haft that number (it's a negative) and the next number would be 0
