standard_description: Use informal arguments to establish facts about the angle sum and exterior angle of triangles, about the angles created when parallel lines are cut by a transversal, and the angle-angle criterion for similarity of triangles. For example, arrange three copies of the same triangle so that the sum of the three angles appears to form a line, and give an argument in terms of transversals why this is so.
problem_activity: Simplify the following expressions:
a.
$$(2^5)^7$$
b.
$$(91^3\times 19\times 103^8)^4$$
c.
$$(p^4q^5r)^9$$
d.
$$2^7\over 3^7$$


aligns: no