University:
College
Course:
College Mathematics
Academic year:

2023
Views:

273

Pages:

2
Author:

anon

Mathematics: Perimeter and Area 1 You should be able to calculate: ❖ Perimeter and area of rectangle ❖ Perimeter and area of triangle ❖ Perimeter and area of compound shapes derived from the above The Perimeter is the total length of all sides of a shape. Perimeter and area of a rectangle A rectangle has 4 sides, so the perimeter is equal to the length of all 4 sides combined Perimeter = a + a + b + b = 2a + 2b = 2(a+b) Area of rectangle = a x b (length x width) Perimeter and area of triangle The perimeter of a rectangle is equal to the length of all three sides. In many cases, Perimeter = a + b + c However, we may not always know the length all 3 sides of the triangle. If the triangle is a right-angled triangle, we can use the pythagoras theorem to deduce the length of any side (given that we already know the length of 2 sides) Pythagoras Theorem: C2 = a2 + b2 The equation can be re-arranged to find the length of any side: Perimeter and area of compound shapes Finding the perimeter of compound shapes is extremely simple, you just need to add up the length of all sides. However, sometimes there may be a few sides with no length, but we can find the length by doing some simple subtracting. For example, the compound shape on the right, we can find the length of the top side by doing 10 – 6 = 4. Finding the area is also extremely simple, all you have to do is split the compound shapes into individual shapes which you could then calculate. For example, for this compound shape we can split it into 2 rectangles, a and b (red line). Afterwards, we can just add up the area of the two rectangles to find the area of the compound shape.