Rectangle (11, 3)

Equations:

A = b ⋅ h

 

 

P =

J =

b ⋅ h

⋅ (b

2

+ h

2

)

----------

 

 

 

12

 

 

 

 

 

2 ⋅ b + 2 ⋅ h

I =

b ⋅ h3

------------

 

 

12

Id = I + A ⋅ d2

Example:

Given: b=4_chain, h=7_rd, d=39.26_in. Set guesses for I, J, and Id in km^4.

Solution: A=28328108.2691_cm^2, P=23134.3662_cm, I=2.9257E–7_km^4, J=1.8211E–6_km^4, Id=2.9539E– 7_km^4.

Regular Polygon (11, 4)

Equations:

1

⋅ n

⋅ L

2

 

 

 

 

 

 

L

 

 

--

 

 

 

 

 

 

 

--

 

 

A = -----4------------------------

P = n ⋅ L

 

rs = -------------

-2--------------

 

180

 

 

 

 

 

 180

TAN

---n-----

 

 

 

TAN-

--n-----

 

 

 

 

 

 

 

 

 

 

 

 

 

L

 

 

 

 

 

 

 

 

 

 

 

---

 

 

n-----–----2--

 

 

 

360---

rv =

--------

----2-------------

- θ =

⋅ 180

β

=

 

 

 

 180

n

 

 

 

 

n

 

 

SIN---

n-----

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Example:

Given: n=8, L= 0.5_yd.

Solution: A=10092.9501_cm^2, P=365.7600_cm, rs=55.1889_cm, rv=59.7361, θ=135_°, β=45_°.

Equation Reference 5-45