WEBVTT
00:00:00.760 --> 00:00:02.640
Find the perimeter of the shape below.
00:00:03.160 --> 00:00:06.600
We’re given a triangle that has three equal sides.
00:00:07.240 --> 00:00:13.400
Each of the sides measures seven and thirty-nine hundredths centimeters.
00:00:14.120 --> 00:00:20.920
We know that all the sides are equal because of the tick marks labelled on the triangle.
00:00:21.680 --> 00:00:29.040
We also know, to find the perimeter of a triangle, we add up all the side lengths.
00:00:29.640 --> 00:00:42.840
In this case, we’ll need to add seven and thirty-nine hundredths plus seven and thirty-nine hundredths plus seven and thirty-nine hundredths.
00:00:43.600 --> 00:00:50.600
We can line them up vertically, making sure we carefully align the decimal points.
00:00:51.080 --> 00:00:57.520
From there, we add the units in the hundredths place, nine plus nine plus nine.
00:00:58.280 --> 00:01:03.000
Nine plus nine plus nine equals 27.
00:01:03.640 --> 00:01:07.880
We’ll write down our seven and carry over our two.
00:01:08.360 --> 00:01:16.400
In the tenths place, we’ll then need to add two plus three plus three plus three.
00:01:17.240 --> 00:01:21.240
Three plus three plus three is nine.
00:01:21.840 --> 00:01:26.320
And if we add two to that, we have 11.
00:01:26.960 --> 00:01:35.000
We’ll write one in the tenths place and then carry over the other one from our 11.
00:01:35.640 --> 00:01:45.240
In our next step, we’ll need to make sure we remember to bring down the decimal place, and then we can add all the digits in the ones place.
00:01:45.920 --> 00:01:55.840
One plus seven plus seven plus seven, seven plus seven plus seven is 21.
00:01:55.840 --> 00:02:01.160
And if you add one to that, you’ll get 22.
00:02:01.560 --> 00:02:07.640
The perimeter would be twenty-two and seventeen hundredths.
00:02:08.320 --> 00:02:14.040
But since we’re measuring a side length, we’ll need to bring down the centimeters.
00:02:14.040 --> 00:02:22.240
The perimeter of this shape is twenty-two and seventeen hundredths centimeters.