Formulas

Question 1

Formula for area of a trapezoid

Answer 1

A = 1/2H (base1+ base2)

Question 2

Formula for area of a triangle

Answer 2

1/2 x H x Base

Question 3

Mitre angle formula

Answer 3

Angle = angle of elbow /( number of PC’s X2) - 2

Question 4

Vertical apex

Answer 4

VH x LD / LD- SD

Question 5

Formula for OG wrapper length

Answer 5

4x square root of Length^2 + offset^2 - L /3

Question 6

Formula for radius point on ogee offset

Answer 6

(Offset2 + length2) / (4x offset)

Question 7

Formula to find throat or heel length

Answer 7

R x 1.57 x Degree/90

Question 8

Velocity pressure formula

Answer 8

VP = (FPM/4005)^2
Or
Pv = Pt - Ps

Question 9

Formula for calculating FPM using VP

Answer 9

FPM = Square root VP x 4005

Question 10

Calculate round duct size with Area

Answer 10

R = square root of area (square inches) / 3.14

Break down =

square feet x144 = square inches

Square inches/3.14 = x

Square root X = Radius of your round duct size X2 = diameter of round duct size

Question 11

Volume of cylinder

Answer 11

3.14xR^2xH

Question 12

What formula is this
Angle/360 x 3.14 x 2 x (throat radius)

Answer 12

Elbow throat S.O.

Question 13

What formula is this
Angle/360 x 3.14 x 2 (heel radius)

Answer 13

Elbow heel S.O.