Set up the equation by writing the number of students in the ratio as a fraction:
3/4= (245-x)/x Cross multiply:
3x= 4(245-x) Multiply on right:
3x= 980-4x Add 4x on both sides:
7x= 980 Divide both sides by 7:
x= 140 this is how many girls there are. And:
245-140= 105= boys
Answer:
We need the following three rigid motions:
i) Reflection around y-axis, ii) Translation three units in the -y direction, iii) Translation four units in the -x direction.
Step-by-step explanation:
We need to perform three operations on pentagon ABCDE to create pentagon A'B'C'D'E':
i) Reflection around y-axis:
(Eq. 1)
ii) Translation three units in the -y direction:
(Eq. 2)
iii) Translation four units in the -x direction:
(Eq. 3)
We proceed to proof the effectiveness of operations defined above by testing point D:
1)
Given.
2)
By (Eq. 1)
3)
By (Eq. 2)
4)
By (Eq. 3)/Result
21x + 28 = 156 - 2
21x = 154 - 28
21x/21 = 126/21
X = 6

Substitute x = 3 in any given equations. I will do in y = - x + 1

Therefore the answer is (3,-2)