### Video Transcript

Find the perimeter of the square ๐ด๐ต๐ถ๐ท below and determine the measure of angle ๐ธ๐ถ๐ท if the measure of angle ๐ต๐ถ๐ธ equals 70 degrees.

There are two parts to this question. The first one is to find the perimeter and the second one is to find the missing angle ๐ธ๐ถ๐ท. So letโs start by recalling that perimeter is the distance all the way around the outside edge of a shape. The first thing to do is to recall that a square has four sides of equal length. That means that the four sides of this square will all be of 60 centimeters. In order to find the perimeter, we can add 60, 60, 60, and 60, or we can work out four multiplied by 60. Either way, weโll get an answer of 240. The units here will be length units of centimeters.

Now that we found the perimeter, letโs see if we can find the measure of angle ๐ธ๐ถ๐ท. Weโre given that the measure of angle ๐ต๐ถ๐ธ is 70 degrees, and we could fill this onto the diagram. Weโll need to recall another fact about the angles in a square. All the interior angles in a square are 90 degrees. So, to find angle ๐ธ๐ถ๐ท, we take angle ๐ท๐ถ๐ต, which is 90 degrees, and subtract the angle ๐ต๐ถ๐ธ, which is 70 degrees, leaving us with 20 degrees.

We can give the two answers to the question: the perimeter is 240 centimeters, and angle ๐ธ๐ถ๐ท is 20 degrees.