2 pontos 3 - A América Pré-
Colombiana, refere-se ao
período da História do
continente Americano,
referente ao:
O
a) () - Período em que o homem
chegou a lua.
O
b) () - Período Depois em que
Colombo Chegou à América.
O
c) () - Período em que Cabral
Chegou ao Brasil.
O
d) () - Período antes da chegada de
Colombo no Continente Americano
O
e) () - Período antes da chegada de
Cabral ao Brasil.​

bd = 9 cm

step-by-step explanation:

in a 30°-60°-90° triangle, the ratio of side lengths is 1 : √3 : 2. that is, the longest side (hypotenuse) is twice the length of the shortest side.

all of the triangles in your geometry are 30°-60°-90° triangles. ac is the hypotenuse of δacd, and the short side of δabc.

the short side ad of δacd will be half the length of ac, so 3 cm. the hypotenuse ab of δabc will be twice the length of ac, so 12 cm. segment bd is the difference of the lengths ab and ad, so is

bd = ab -ad

bd = 12 cm - 3 cm = 9 cm

comment on side length ratios

you can figure the ratios of side lengths in a 30°-60°-90° triangle by considering the trig ratios of the angles. or you can figure the length of the altitude of an equilateral triangle of side length 2 using the pythagorean theorem.

you can put this in your 11 sentence summary

" most of the money would be invested in innovation, economic convergence."