Me understand this problem! i don’t understand the methods to understand how to solve it

Perimeter at the big rectangle is 156 cm.

Step-by-step explanation:

Let's see how to calculate it.

1. First of all you know that perimeter in the blue one is 20cm, so imagine this:

L (long side); S (short side)

2L + 2S =20

and we consider that L = 4S

So, solving the equation:

2.4S + 2S =20

10S=20

S=20/10

S=2

L=8

2. Side at the gold square is 8, the same at the long side in the blue rectangle. So, if you see on the right side in the big one, we got 2 + 8 + 8 + (?). Take a look to the green. Green square is the gold + a short piece and you can understand the short piece as 2 short sides from the blue. If we give numbers we have 8 + 2 + 2, 12.

Now, 2+8+8+12 = 30cm

3. Let's go to the long side in the big one.

We have long side from blue (8) and as you see, side at the orange square must be side at the yellow + short at the blue, so 8+2 =10. We have four oranges square so 10+10+10+10=40, and +8 =48

4. Now that we have the two sides in the big one, let's find the perimeter with the rectangle formula:

2L + 2S =P

2.48 + 2.30 = 156 cm.

just take the area of the square and then the area of the circle then subtract the circle area from the squares area

step-by-step explanation: