The unknown is how many girls and boys are in the class.
Divide 315,530,612 by 3,539,225 to get 89 people per square mile (rounded)
9u means you're multiplying 9 into that vector, both components. Same with the 2v. 9*3 = 27 and 9*-1 = -9, so your new vector u is <27, -9>. Now let's do v. 2* -6 (twice) = -12, so your new v vector is <-12, -12>. Add those together now, first components of each and second components of each. 27 + (-12) = 15; -9+(-12)=-21. So the addition of those gives us a final vector with a displacement of <15, -21>
Let's see
In ∆ABE and ∆CBE
- BE=BE(Common side)
- AE=EC[Diagonals of a parallelogram bisect each other]
- <AEB=<BEC[90°]
So by
SAS congruence the triangles are congruent
AB=BC
Fact:-
It's already given AC is perpendicular to BD
- It means diagonals are perpendicular to each other
According to general property of rhombus this parallelogram is also a rhombus.
So sides are equal hence AB =BC