🎬 Perimeter and area · Class 7 maths · 3:10
Perimeter and area: Class 7 maths video
Master perimeter and area of squares, rectangles, triangles, parallelograms, and circles with Captain Calc in this exciting Class 7 maths mission!
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Transcript
0:00 Class 7 maths. Perimeter and area.
0:04 Welcome aboard, superhero cadet!
0:07 Captain Calc needs your help to measure shapes and secure HQ boundaries.
0:12 Perimeter and Area of Squares and Rectangles.
0:16 Perimeter is the total length around the boundary of a flat shape.
0:21 Area measures the surface space enclosed inside the boundary of a shape.
0:26 Try this one. Find the perimeter and area of a rectangle with length 8 m and width 5 m.
0:34 Perimeter = 2 × (length + width) = 2 × (8 + 5) = 2 × 13 = 26 m.
0:44 Area = length × width = 8 × 5 = 40 m².
0:50 So the answer is Perimeter is 26 m and Area is 40 m²..
0:56 Area of Parallelograms.
0:59 A parallelogram is a four-sided shape with opposite sides parallel and equal.
1:05 Any side of a parallelogram can be chosen as its base.
1:09 Try this one. Find the area of a parallelogram with base 10 cm and height 7 cm.
1:17 Area = base × height.
1:20 Area = 10 × 7 = 70 cm².
1:25 So the answer is Area is 70 cm²..
1:29 Area of Triangles.
1:31 A triangle is formed by dividing a parallelogram into two equal parts along a diagonal.
1:38 The formula for the area of a triangle is Area = (1/2) × base × height.
1:45 Try this one. Find the area of a triangle with base 12 cm and height 5 cm.
1:53 Area = (1/2) × base × height.
1:58 Area = (1/2) × 12 × 5 = 6 × 5 = 30 cm².
2:06 So the answer is Area is 30 cm²..
2:10 Circles: Circumference and Area.
2:13 The distance around a circle is called its circumference, given by Circumference = 2 × π × r.
2:21 The diameter is double the radius (d = 2 × r).
2:26 Try this one. Find the circumference of a circular plate with radius 7 cm. (Use π = 22/7)
2:36 Circumference = 2 × π × r.
2:40 Circumference = 2 × (22/7) × 7 = 44 cm.
2:47 So the answer is Circumference is 44 cm..
2:51 Your turn. The perimeter of a square floor is 36 m. What is the length of one side in m? Pause the video, and try it.
3:03 The answer is 9.
3:05 Well done! Now try the practice and the quiz in this lesson on LearnFun.
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