Answer:
Option 4, 64 cm^2
Step-by-step explanation:
The polygon in the shape of a star can be made to be easier to find the area of by cutting it into triangle. For all the "point edges" of the star, we can cut them in half from the vertex to create two right-angled triangles at each edge.
The formula of the area of a triangle is bh/2: the height is given as 6cm, the base is 4cm /2 (after you cut it in half) and so is 2 cm. Since the edges can be cut into two, there are 8 right angled triangles at the edges in total.
To find the area of them:
A=8(bh/2)=8(2*6/2)=48 cm^2
However, we are still missing the part at the centre we haven't found the area of, the square. The area of a square is given by the square of the side length(4cm). Thus, A=4*4=16cm^2
Adding the areas of all the edges and the square:
48 + 16 = 64cm^2
Hence, the area of the polygon is 64cm^2
Year 1: 7lbs x 3years= 21lbs
Year 2: 21lbs x 3years = 63lbs
Answer:
20 inches x 26 inches
Step-by-step explanation:
set up an equation: (2x)(x+7)=520
now just solve it
2x^2+14x=520
x^2+7x-260 = 0
factor: (x-13)(x+20)
x = 13 and -20
13 is the only one that works because you can't have a negative side length
13+7=20
13*2=26
lmk if you don't understand how to solve that equation
Answer:
5cm by 1.95cm
Step-by-step explanation:
Let the length of the rectangle be x
Let the width be y
Perimeter of a rectangle = 2x + 2y
If the initial perimeter of a rectangle is about 13.9 cm, then;
13.9 = 2x + 2y ..... 1
If when the width is double the perimeter is 17.8cm, then;
17.8 = 2x + 4y ..... 2
Subtract 1 from 2;
13.9 - 17.8 = 2y - 4y
- 3.9 = -2y
y = 3.9/2
y = 1.95 cm
Substitute y = 1.95 into 1 to get x;
From 1;
13.9 = 2x + 2y
13.9 = 2x + 2(1.95)
13.9 = 2x + 3.9
2x = 13.9-3.9
2x = 10
x = 5 cm
Hence the dimension of the smaller triangle is 5cm by 1.95cm
