Creating a text box to 
- describe the construction
- refer to objects in the construction
- show static values or dynamic values from construction

Use of input bar to - 
- compute derived values/variables
- define objects 
- define algebraic functions

What did we learn in this lecture

Constructing a Text box and using the Input bar

A = (-8.575138543652486, 5.003501353393165)
B = (-4.50969103350679, 8.960536929934982)
C = (-0.5165181457636794, 4.913158075389931)
t1, c, a, b = Polygon(A, B, C)
α = Angle(A, B, C)
β = Angle(C, A, B)
γ = Angle(B, C, A)
δ: α + β + γ
text1: "∡ABC = " + α + " ∡BCA =  " + β + " ∡CAB =  " + γ + "
Sum of measures of angles of a triangle
= " + α + "+" + β + "+" + γ + " = " + δ + ""
d = true

Tool: SquareTool
Tool2[ <Number>, <Point> ]
Input: side, A
Output: poly1

B = Point(Circle[A, side])
a = Segment(A, B)
c = Circle(A, side)
b = OrthogonalLine(A, a)
C = Intersect(c, b, 2)
d = Circle(C, side)
e = OrthogonalLine(C, b)
D = Intersect(d, e, 1)
poly1, a_1, b_1, d_1, c_1 = Polygon(A, B, D, C)