https://www.khanacademy.org/math/cc-third-grade-math/3rd-perimeter/imp-perimeter/v/introduction-to-perimeter 2023-04-19T11:35:31.910148755Z Perimeter: introduction Perimeter is a math concept that measures the total length around the outside of a shape. To find the perimeter, you add together the lengths of all the sides. This works for any shape, including triangles, rectangles, pentagons, and even irregular polygons. Sal Khan video https://cdn.kastatic.org/googleusercontent/aTvq7f3uGIpqeoqnKTdxUkoGyVejTcBvBXqaj7wzF4xDy1JAs8xn1oz1vrTQbSsF6zh-V3eQkAXzKg0hNkdL7sqR Perimeter: introduction Perimeter is a math concept that measures the total length around the outside of a shape. To find the perimeter, you add together the lengths of all the sides. This works for any shape, including triangles, rectangles, pentagons, and even irregular polygons. https://cdn.kastatic.org/ka-youtube-converted/9uwLgf84p5w.mp4/9uwLgf84p5w.mp4 201 Perimeter and Area https://www.khanacademy.org/math/cc-third-grade-math/3rd-perimeter/imp-perimeter/v/perimeter-of-a-shape 2023-05-12T21:01:01.897246564Z Perimeter of a shape To find the perimeter of a shape, you add up the lengths of all the sides. For a square or pentagon, it's even easier - you can multiply the length of one side by the number of sides to get the total perimeter. Sal Khan video https://cdn.kastatic.org/googleusercontent/UlxL_EqGkpGn6DXpypd7dfdMh0dMCzgH7tj1Smbre-y-J374xF8cOAWrG2m8DLVWyqNTudJYM3xJesJdtnHD5VpK Perimeter of a shape To find the perimeter of a shape, you add up the lengths of all the sides. For a square or pentagon, it's even easier - you can multiply the length of one side by the number of sides to get the total perimeter. https://cdn.kastatic.org/ka-youtube-converted/sJmLjUj_h68.mp4/sJmLjUj_h68.mp4 123 Perimeter and Area https://www.khanacademy.org/math/cc-third-grade-math/3rd-perimeter/imp-perimeter/e/perimeter_1 2021-06-30T20:49:36Z Find perimeter by counting units Calculate the perimeter of a rectangle from its side lengths. Ben Eater exercise https://www.khanacademy.org/math/cc-third-grade-math/3rd-perimeter/imp-perimeter/e/perimeter-2 2025-02-10T05:04:39.155459793Z Find perimeter when given side lengths Find perimeter of figures when given an image or context.   Lindsay Spears exercise https://www.khanacademy.org/math/cc-third-grade-math/3rd-perimeter/perimeter-of-polygons-with-missing-side-lengths/v/finding-missing-a-side-length-when-given-perimeter-math-3rd-grade-khan-academy 2023-04-19T11:35:31.910148755Z Finding missing side length when given perimeter The video illustrates how to find the lengths of unknown sides on a shape by using the given perimeter and the lengths of known sides. Two examples are given, and in each case, the missing side lengths are determined to be 5 units. Lindsay Spears video https://cdn.kastatic.org/googleusercontent/SR9KKRii0BvLtSZDwoLs7pD--qohmq-m4voTY1cPpTe3Qj303N2tLyVCNTB1OUwyazNz2EAD48PNonW4NknfEAnv Finding missing side length when given perimeter The video illustrates how to find the lengths of unknown sides on a shape by using the given perimeter and the lengths of known sides. Two examples are given, and in each case, the missing side lengths are determined to be 5 units. https://cdn.kastatic.org/ka-youtube-converted/_sQ3dqhLsIw.mp4/_sQ3dqhLsIw.mp4 295 Perimeter and Area https://www.khanacademy.org/math/cc-third-grade-math/3rd-perimeter/perimeter-of-polygons-with-missing-side-lengths/e/find-a-missing-side-length-when-given-perimeter 2025-06-24T14:43:14.98588327Z Find a missing side length when given perimeter Find a missing side length for a figure when given the perimeter. Lindsay exercise https://www.khanacademy.org/math/cc-third-grade-math/imp-geometry/imp-count-unit-squares-to-find-area/v/introduction-to-area-and-unit-squares 2023-04-25T08:31:06.154925218Z Intro to area and unit squares Together, we'll explore a video introducing area by comparing two figures' space on a surface. Using unit squares, we'll measure their areas, emphasizing the importance of a unit square for measuring various shapes. Sal Khan video https://cdn.kastatic.org/googleusercontent/G-62Rh_4vTCNgad_3844V2-dLdcsVlE66lGxrlyYkfJnePih2nSuzfvhbDh0fH185HuchLgyA9OEp8aa4AfY2Bko Intro to area and unit squares Together, we'll explore a video introducing area by comparing two figures' space on a surface. Using unit squares, we'll measure their areas, emphasizing the importance of a unit square for measuring various shapes. https://cdn.kastatic.org/ka-youtube-converted/A7zPgMV4eTM.mp4/A7zPgMV4eTM.mp4 257 Perimeter and Area https://www.khanacademy.org/math/geometry-home/geometry-area-perimeter/geometry-perimeter/v/perimeter-and-area-basics 2023-05-12T21:01:01.897246564Z Perimeter & area Perimeter is the distance around the outside of a shape. For example, if you walk around the edge of a playground, you're measuring its perimeter. Area is the amount of space inside a shape. For example, if you want to put new tiles on your kitchen floor, you need to know the area of the room to know how many tiles to buy. Sal Khan video https://cdn.kastatic.org/googleusercontent/6PHejb3nLknlESjEf8yilpF588ztG96Md4U0G0F2kXYTFr7K_5SyjKX3almyy55tUq_uVPO_kJCJ4NRCR1Y_SIUy Perimeter & area Perimeter is the distance around the outside of a shape. For example, if you walk around the edge of a playground, you're measuring its perimeter. Area is the amount of space inside a shape. For example, if you want to put new tiles on your kitchen floor, you need to know the area of the room to know how many tiles to buy. https://cdn.kastatic.org/ka-youtube-converted/LoaBd-sPzkU.mp4/LoaBd-sPzkU.mp4 505 Perimeter and Area https://www.khanacademy.org/math/cc-third-grade-math/imp-geometry/imp-area-introduction/e/understand-area 2026-03-05T15:40:37.577083627Z Understand area Practice finding the area of different figures.  Lindsay exercise https://www.khanacademy.org/math/cc-third-grade-math/imp-geometry/imp-area-formula-intuition/v/rectangle-area-as-product-of-dimensions-same-as-counting-unit-squares 2021-07-07T20:19:26Z Counting unit squares to find area formula Sal uses unit squares to see why multiplying side-lengths can also find the area of rectangles.    Sal Khan video https://cdn.kastatic.org/googleusercontent/stlR2hLpfqUfhlaLA1rKy8H9zxDvxEGD6edqlv1x1mvDZt_TDdE-iide8P6i7NGR_cnNQdkRDwsjUpENXZzeGTc Counting unit squares to find area formula Sal uses unit squares to see why multiplying side-lengths can also find the area of rectangles.    https://cdn.kastatic.org/ka-youtube-converted/DRg2VCo8lP0.mp4/DRg2VCo8lP0.mp4 320 Perimeter and Area https://www.khanacademy.org/math/cc-third-grade-math/imp-geometry/imp-multiply-to-find-area/e/area-of-squares-and-rectangles 2025-09-13T00:00:42.547282073Z Area of rectangles Find area of rectangles and squares by multiplying side lengths. Lindsay exercise https://www.khanacademy.org/math/cc-third-grade-math/imp-geometry/imp-multiply-to-find-area/v/finding-missing-side-when-given-area-math-3rd-grade-khan-academy 2021-07-07T20:19:25Z Finding missing side when given area Lindsay finds the missing side length on a rectangle when given the area of the rectangle.  Lindsay Spears video https://cdn.kastatic.org/googleusercontent/4UWiKYtz-XuI6D4Frqz2ieJ0yLETguWV59xwm8xc3ts4PeHKRNflaTcs04S-sjB0PXwfpIvkcj0Dhhz00vaLkPA Finding missing side when given area Lindsay finds the missing side length on a rectangle when given the area of the rectangle.  https://cdn.kastatic.org/ka-youtube-converted/_JdgDBzQ0Us.mp4/_JdgDBzQ0Us.mp4 184 Perimeter and Area https://www.khanacademy.org/math/cc-third-grade-math/imp-geometry/imp-multiply-to-find-area/e/find-a-missing-side-length-when-given-area-of-a-rectangle 2024-09-14T11:44:41.070959017Z Find a missing side length when given area Practice finding a missing side length on a rectangle when given the other side length and the area. Lindsay exercise