KELILING DAN LUAS PERSEGI - SEGITIGA DAN SEGIEMPAT (12) - MATEMATIKA SMP KELAS 7

Summary

In this engaging mathematics lesson for 7th-grade students, Wahyudi explains the concept of squares, focusing on their properties, perimeter, and area. The lesson highlights key characteristics such as equal sides, right angles, and the relationship between diagonals. Wahyudi then demonstrates how to calculate the perimeter and area of squares using simple formulas. The script also includes practical examples and problem-solving techniques, such as determining the perimeter and area when given specific dimensions. The lesson is designed to help students understand and apply these concepts effectively in real-life situations, making math accessible and enjoyable.

Takeaways

• 😀 A square is a quadrilateral with four equal sides and four right angles.
• 😀 The perimeter of a square is the sum of all its sides, and can be calculated as 4 times the length of one side.
• 😀 The area of a square is the length of one side squared (side × side).
• 😀 The diagonals of a square are equal in length and intersect at right angles.
• 😀 To calculate the perimeter of a square, multiply the side length by 4.
• 😀 To find the area of a square, square the length of one side.
• 😀 If the perimeter of a square is known, divide it by 4 to find the length of one side.
• 😀 If the area of a square is known, take the square root of the area to find the length of one side.
• 😀 Real-life applications of square geometry include tiling floors and landscaping with trees planted at regular intervals around a square garden.
• 😀 For example, to tile a square floor with 30 cm by 30 cm tiles, divide the length of the floor by the tile size to calculate how many tiles are needed.
• 😀 When planting trees around a square garden, divide the perimeter by the distance between trees to find the total number of trees needed.

Q & A

What are the properties of a square?

A square is a quadrilateral with four equal sides and four right angles (90°). Its diagonals are equal in length and intersect at right angles.

How do you calculate the perimeter of a square?

The perimeter of a square is calculated by adding up the lengths of all four sides. Since all sides are equal, the formula is P = 4s, where 's' is the length of one side.

What is the formula for the area of a square?

The area of a square is calculated by squaring the length of one side. The formula is A = s², where 's' is the length of a side.

If the perimeter of a square is 52 cm, what is the area?

To find the area, first divide the perimeter by 4 to get the side length: 52 ÷ 4 = 13 cm. Then, square the side length: 13² = 169 cm².

How do you calculate the perimeter of a square if the area of a rectangle is equal to the area of the square?

First, calculate the area of the rectangle by multiplying its length and width. Then, find the side length of the square by taking the square root of the area. The perimeter is then calculated as P = 4s.

A floor is shaped like a square with side lengths of 6 meters. How many 30 cm by 30 cm tiles are needed to cover the floor?

Convert the side length of the floor to centimeters: 6 m = 600 cm. Divide the floor's side length by the side length of a tile: 600 ÷ 30 = 20 tiles per side. Multiply the number of tiles along one side by itself: 20 × 20 = 400 tiles.

How many pine trees are needed to surround a square garden with a side length of 30 meters, with 3 meters between each tree?

Divide the side length of the garden (30 m) by the spacing between trees (3 m): 30 ÷ 3 = 10 trees per side. Since the garden has four sides, multiply the number of trees per side by 4: 10 × 4 = 40 trees.

Why are the diagonals of a square always equal in length?

The diagonals of a square are equal because all four sides are equal in length, and the angles between them are 90°, which causes the diagonals to bisect each other at right angles and be of equal length.

What does the term 'perimeter' mean in geometry?

The perimeter refers to the total distance around the outside of a shape. In the case of a square, it is the sum of the lengths of all four sides.

Can the formula for the area of a square be used for other quadrilaterals?

No, the formula for the area of a square (A = s²) only applies to squares. Other quadrilaterals, such as rectangles or trapezoids, have different formulas for calculating area.