The length of a side of an equilateral triangle is x - 4.5. first express its perimeter as a sum. next express its perimeter as a product. explain why the two expressions are equivalent.

Equilateral triangle means all sides have equal length.
Perimeter
As a sum: (x-4.5)+(x-4.5)+(x-4.5)
As a product: 3 * (x-4.5)
They are equivalent because 3 times a number is just the sum of three of the number.

This polygon has 4 sides
180(4-2) = 180(2) = 360 degree
80+90+2x + 3x = 360
170+5x = 360
5x = 190
x= 38
measure of angle t is 2(38)= 76
the answer is c. trust me
hope this !