3x - 1 = 2x
3x = 2x + 1
3x - 2x = 1
x = 1
A² = c² - b²
a² = 21² - 13 ²
a² = 441 - 169
a² = 272
a = √272 = 16.49242 ≈ 16.49
Answer : D ) 16.49
A. 250+0.08s=410
-250. -250
0.08s= 160
0.08s/0.08s 160/0.08s
S=2000
If one square is divided into 9 smaller equal squares, then they have to be arranged in 3 lines of 3, that is 3 smaller equal squares per side of the original big square. That said, the area of the big square is equal to the multiplication of 3 small squares sides times 3 small squares sides, call x the length of the small squares.
So,
area = 9 = 3x*3x
9x^2 = 9
x^2 = 1
x = 1
therefore the smaller squares have sides of 1 unit