12. ∆ABD is similar to ∆PQD, so
QD/z = BD/x
Likewise ∆CDB is similar to ∆PQB, so
QB/z = BD/y
Since QD + QB = BD, you have
QD/z + QB/z = BD/x + BD/y
BD/z = BD/x + BD/y
Dividing by BD gives the desired result:
1/x + 1/y = 1/z
13. Triangles ABD, BCD, and ACB are all similar. This means
AB/AC = AD/AB
AB² = AC×AD = (4 cm)×(9 cm)
AB² = 36 cm²
AB = 6 cm
and
BD/CD = AD/BD
BD² = CD×AD = (5 cm)×(4 cm)
BD² = 20 cm²
BD = 2√5 cm
Answer:
Get the equation in the form y = ax2 + bx + c.
Calculate -b / 2a. This is the x-coordinate of the vertex.
To find the y-coordinate of the vertex, simply plug the value of -b / 2a into the equation for x and solve for y. This is the y-coordinate of the vertex.
The answer is B. She sells each orange for $0.50 and the question is asking for the total amount of money she will make by selling a certain amount of oranges. t represents the total so the equation will to equal to t. c is the number of oranges she will sell so c multiplied by $0.50 will give the total amount of money she will make.
Answer:
A and D
Step-by-step explanation:

As 40/6 form a ratio and can be expressed in a p/q form where p=40 and q=6, it is rational
As 11 forms a ratio(11:1) and can be expressed in a p/q form where p=11 and q=1, it too is rational
Answer:
12
Step-by-step explanation:
15/1.25 is 12