MIRB16

Let x be how much they have aged when the sum of their ages is 40.

12+x+8+x=40

20+2x=40

2x=20

x=10

Therefore Percy will be 8+10=18 years old when the sum of their ages is 40.

If you connect the radii of each circle to its tangent points with the other circles, you have a square with side lenth 2r.

The diagonal of this square is $2r\sqrt{2}$ by the pythagorean theorem. 

The diagonal is r+small circle diameter+r = $2r\sqrt{2}$

Subtracting both sides by 2r, the diameter of the samll circle should be $2r\sqrt{2}-2r$ which means the radius should be $\frac{2r\sqrt{2}-2r}{2}=\sqrt{2}r-r=r(\sqrt{2}-1)$.

THANK YOU ALL AND HAPPY B-DAY MAX

I got it!

Thank you so much!! That really helped!

first, we can subtract the area of the white from the area of the square. The top left triangle is x by 2x so the area is x^2. The triangle on the right is 3x by 4x so the area is 6x^2 the area of the bottom triangle is 2x by 4x so the area of that is 4x^2. the area of the whole square is 4x*4x=16x^2 16x^2-11x^2=5x^2

https://web2.0calc.com/questions/help-please_81597

15.75

this is a proportion

lets say that 5.25 to 6 is equal to x to 18. notice that 18 is 3*6 so in order to find x we need to multiply 5.25 by 3 which is 15.75

I got it and its 10901 but thanks!!!

got it nvm!!!!