WEIGHTS  AND  MEASURES  19

Or  multiply  the  square  of  diameter  by  .7854

Or  multiply  the  square  of  circumference  by  .07958

Or  multiply  the  square  of  one-half  diameter  by  3.1416

To  Find  Side  of  an  Inscribed  Square:
Multiply  diameter  by  .7071
Or  multiply  circumference  by  .2251
Or  divide  circumference  by  4.4428

To  Find  Side  of  a  Square  of  Equal  Area:
Multiply  diameter  by  .8862
Or  divide  diameter  by  1.1284
Or  multiply  circumference  by  .2821
Or  divide  circumference  by  3.545

Square:

A  side  multiplied  by  1.4142  equals  diameter  of  its  circumscrib-
ing circle

A  side  multiplied  by  4.443  equals  circumference  of  its  circum-
scribing circle

A  side  multiplied  by  1.1284  equals  diameter  of  a  circle  of  equal
area

A  side  multiplied  by  3.545  equals  circumference  of  an  equal
circle

To  Find  the  Area  of  an  Ellipse:

Multiply  the  product  of  its  axes  by  .7854

Or  multiply  the  product  of  its  semi-axes  by  3.14159

RULES  RELATIVE  TO  OTHER  GEOMETRICAL  FIGURES

Contents  of  cylinder  =  area  of  end  X  length

Contents  of  wedge  =  area  triangular  base  X  altitude

Surface  of  cylinder  =  length  X  circumference  +  area  of  both  ends

Surface  of  sphere  =  diameter    squared  X  3.1416,   or  =  diameter

X  circumference

Contents  of  sphere  =  diameter  cubed  X  .5236
Contents  of  pyramid  or  cone,  right  or  oblique,  regular  or  irregular

=  area  of  base  X  one-third  altitude


20  APPLIED  SCIENCE

Area  of  triangle  =  base  X  one-half  altitude

Area  of  parallelogram  =  base  X  altitude

Area  of  trapezoid  =  altitude  X  one-half  the  sum  of  parallel  sides

Questions

1.  What  measuring  instrument  is  used  to  measure  the  length
of  a  9-ft.  plate?     36-ft.  boat?    20-ft.  wind-shield?

2.  What  measuring  instrument  is  used  to  measure  the  width
of  lumber?     Length  of  bolts?    Screws?

3.  What  measuring  instrument  is  used  to  measure  the  diameter
of  a  cylindrical  metal  bar?     Balls?

4.  What  measuring  instrument  is  used  to  measure  the  inside
diameter  of  pipes?    Elbows?

5.  What  measuring  device  is  used  in  measuring  the  length  and
width  of  a  table?

6.  A  foreman  desires  to  measure  the  length  of  the  shop  floor.
