MatheAss 10.0 − 3‑dim. Geometry

Coordinate systems

With this program, three‑dimensional Cartesian coordinates can be converted into spherical or cylindrical coordinates and vice versa.

Cartesian           polar                           cylindrical
   x  =  1              r  =  1.7320508           ρ  =  1.4142136
   y  =  1             φ  =  45°                      φ  =  45°  
   z  =  1             Θ =  35.26439°            z  =  1      

Platonic solids

The program calculates the five Platonic solids — tetrahedron, hexahedron, octahedron, dodecahedron and icosahedron — when edge length, face height, space height, inradius, circumradius, volume or surface area are given.

Tetrahedron

Given:
¯¯¯¯¯
  Circumradius rc = 1

Results:
¯¯¯¯¯¯
                 Edge a = 1,6329932
         Apothem h1 = 1,4142136
            Altitude h2 = 1,3333333
             Inradius ri = 0,33333333
             Volume V = 0,51320024
             Surface S = 4,6188022

Hexahedron

Given:
¯¯¯¯¯
                 Inradius ri = 1

Results:
¯¯¯¯¯¯
                     Edge a = 2
   Face Diagonal d1 = 2,8284271
   Body Diagonal d2 = 3,4641016
      Circumradius rc = 1,7320508
                 Volume V = 8
                 Surface S = 24

Octahedron

Given:
¯¯¯¯¯
             Inradius ri = 1/sqrt(3)

Results:
¯¯¯¯¯¯
                 Edge a = 1,4142136
         Apothem h1 = 1,2247449
            Altitude h2 = 2
  Circumradius rc = 1
             Volume V = 1,3333333
             Surface S = 6,9282032

Dodecahedron

Given:
¯¯¯¯¯
   Face Diagonal d = 2

Results:
¯¯¯¯¯¯
                   Edge a = 1,236068
      Face Altitude h = 1,902113
    Circumradius rc = 1,7320508
               Inradius ri = 1,3763819
               Volume V = 14,472136
               Surface S = 31,543867

Icosahedron

Given:
¯¯¯¯¯
            Altitude h2 = 2

Results:
¯¯¯¯¯¯
                 Edge a = 1,0514622
         Apothem h1 = 0,910593
  Circumradius rc = 1
             Inradius ri = 0,79465447
             Volume V = 2,5361507
             Surface S = 9,5745414

Other solids

The program calculates all quantities of a regular prism, a right circular cylinder, a square pyramid, a right circular cone or a sphere, when two of them are given.

The prism

Given:
¯¯¯¯¯
           Vertices  n = 6
  Circumradius rc = 1
            Volume  V = 1

Results:
¯¯¯¯¯¯
                Edge  a = 1
             Altitude  h = 0,38490018
             Inradius ri = 0,8660254
                Base  B = 2,5980762
            Surface  S = 7,5055535

The circular cylinder

Given:
¯¯¯¯¯
                 Radius r = 1
               Volume V = 1

Results:
¯¯¯¯¯¯
                Altitude h = 0,31830989
           Perimeter p = 6,2831853
                   Base B = 3,1415927
  Lateral Surface L = 2
               Surface S = 8,2831853

The square pyramid

Given:
¯¯¯¯¯
               Edge  a = 1
           Volume  V = 1

Results:
¯¯¯¯¯¯
   Lateral edge  s = 3,082207
           Altitude h1 = 3
        Apothem h2 = 3,0413813
           Surface  S = 7,0827625
               Face  A = 1,5206906

The circular cone

Given:
¯¯¯¯¯
                Altitude h = 1
               Surface S = 6

Results:
¯¯¯¯¯¯
                 Radius r = 0,86994247
             Apothem s = 1,3254433
               Volume V = 0,79251901
  Lateral Surface L = 3,622443
                   Base B = 2,377557

The sphere

Given:
¯¯¯¯¯
          Surface S = 1

Results:
¯¯¯¯¯¯
            Radius r = 0,28209479
       Diameter d = 0,56418958
      Perimeter p = 1,7724539
          Volume V = 0,094031597

Parallel circle α = 48°
           Radius r' = 0,18875826
      Perimeter u' = 1,1860031

Line through 2 points

Line through  A(1|1|1), B(2|5|6)

Parametric representation
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
  ->  ⎧ 1 ⎫     ⎧ 1 ⎫
  x = ⎪ 1 ⎪ + t·⎪ 4 ⎪
      ⎩ 1 ⎭     ⎩ 5 ⎭

Distance from origin
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
  d = 0,78679579

Position to the xy plane
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
 Orthogonal projection: 4·x - y = 3
 Point of intersection: S1(0,8|0,2|0)
 Angle of intersection: 50,490288°

Position to the yz plane
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
Orthogonal projection: 5·y – 4·z = 1
Point of intersection: S2(0|-3|-4)
Angle of intersection: 8,8763951°

Position to the xz plane
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
Orthogonal projection: 5·x - z = 4
Point of intersection: S3(0,75|0|-0,25)
Angle of intersection: 38,112927°

Plane through 3 points

Plane through the points
A(1|2|3), B(2|3|3), C(1|0|1)

Point-slope-form
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
->  ⎧ 1 ⎫     ⎧ 1 ⎫     ⎧ 0 ⎫
x = ⎪ 2 ⎪ + r·⎪ 1 ⎪ + s·⎪ 1 ⎪
    ⎩ 3 ⎭     ⎩ 0 ⎭     ⎩ 1 ⎭

Equation in coordinates
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
x - y + z = 2

Distance from origin
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
d = 1,1547005

Trace points
¯¯¯¯¯¯¯¯¯¯¯¯
  Sx(2|0|0)
  Sy(0|-2|0)
  Sz(0|0|2)

Sphere through 4 points

Sphere through the points
A(1|0|0), B(0|2|0), 
C(0|0|3), D(1|0|1)

Normal form
¯¯¯¯¯¯¯¯¯¯¯
    | ->   ⎧-2,5 ⎫ |2 
K : | x  - ⎪-0,5 ⎪ |  = 12,75
    |      ⎩ 0,5 ⎭ |

Center and radius
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
  M(-2,5|-0,5|0,5)
  r = 3,5707142

Intersections in space

The program calculates intersections of lines, planes and spheres.

two lines


    ->  ⎧ 5 ⎫     ⎧ 0 ⎫
g : x = ⎪ 0 ⎪ + r·⎪ 1 ⎪
        ⎩ 0 ⎭     ⎩ 1 ⎭

    ->  ⎧ 0 ⎫     ⎧ 1 ⎫
h : x = ⎪ 5 ⎪ + s·⎪ 0 ⎪
        ⎩ 0 ⎭     ⎩ 1 ⎭

Intersection point : S(5|5|5)

Angle of intersection: 60°

Distances from the origin:  
  d(O,g)=5  d(O,h)=5

plane and line


    ->  ⎧ 5 ⎫     ⎧ 0 ⎫
g : x = ⎪ 0 ⎪ + r·⎪ 1 ⎪
        ⎩ 0 ⎭     ⎩ 1 ⎭

E : x + y + z = 5

Intersection point :  
       S(5|0|0)

Angle of intersection:  
       α = 54.73561°

sphere and line


     ->  ⎧ 1 ⎫     ⎧ 1 ⎫
 g : x = ⎪ 0 ⎪ + r·⎪ 1 ⎪
         ⎩ 0 ⎭     ⎩ 1 ⎭

K : M(5|5|5) ,  r = 5

Intersection points :
 S1(2.8187|1.8187|1.8187)
 S2(8.5147|7.5147|7.5147)

Chord length :
 s = 9.8657657

two planes

Given the two planes:
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
E1 : 5·x – 2·y = 5
E2 : 2·x - y + 5·z = 8

Intersection line:
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
    ->  ⎧-11 ⎫     ⎧ 10 ⎫
g : x = ⎪-30 ⎪ + r·⎪ 25 ⎪
        ⎩  0 ⎭     ⎩  1 ⎭

Distance from origin:
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
  d = 1,5057283

Intersection angle:
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
  α = 65,993637°

two spheres

Given the two spheres:
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
K₁ : M₁(3|3|3) ,  r₁ = 3
K₂ : M₂(1|1|1) ,  r₂ = 3

Intersection circle:
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
M(2|2|2), r = 2,4494897

Intersection plane :
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
  E : x + y + z = 6

sphere and plane

Plane :
¯¯¯¯¯¯¯
 E : 5·x – 4·y + 5·z = -3

Sphere:
¯¯¯¯¯¯¯
     | ->   ⎧ 1 ⎫|2
 K : | x  - ⎪ 2 ⎪| = 16
     |      ⎩ 3 ⎭|

Intersection circle :
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
  M(-0,1363636|2,909091|1,863636)
  r = 3,5483671


Distances on the sphere   (New in version 9.0 from December 2021)

The program calculates the distance between two points on a sphere. Several functions of MatheAss are combined for this purpose.

Radius of the sphere
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
   r = 6371

GPS decimal
¯¯¯¯¯¯¯¯¯¯¯
  Berlin :52.523403, 13.4114
New York :40.714268, -74.005974

GPS dms
¯¯¯¯¯¯¯
  Berlin :52°31'24.2508"N, 13°24'41.04"E
New York :40°42'51.3648"N, 74°0'21.5064"W

...

Distance
¯¯¯¯¯¯¯¯
   d = r · α [rad] = 6385,112