Answer:
Vertical angles
Step-by-step explanation:
: If two angles are vertical angles, then they're congruent (see the above figure). Vertical angles are one of the most frequently used things in proofs and other types of geometry problems, and they're one of the easiest things to spot in a diagram. Don't neglect to check for them!
Answer:
D
Step-by-step explanation:
Because in D, there no x-value that are repeating in the list.
For example A, the value 8 and -8 are being repeated twice, which makes this relation not a fuction.
Answer:
Sister = 15 years old
Brother = 12 years old
Step-by-step explanation:
Right now, if the brother is B years old and the sister is S years old, B = (4/5)S because the ratio from brother to sister is 4:5, so if one unit is X, B = 4X and S = 5X
Three years ago, the brother was B-3 years old and the sister was S-3 years old. Keeping one unit as X, we have
B = 3X
S = 4X
B-3 = (3/4)(S-3)
Therefore, we have a system of equations
B = (4/5)S
B-3 = (3/4)(S-3)
Substitute (4/5)S for B into the second equation to only have one variable
(4/5)S - 3 = (3/4)(S-3)
(4/5)S - 3 = (3/4)S - 9/4
add 3 to both sides and subtract (3/4)S from both sides to isolate the variable and its coefficient
(1/20)S = 3/4
multiply both sides by 20 to isolate the S
S = 15
B = (4/5)S = 12
Answer:
X=4
Step-by-step explanation:
(3X/2) - (X/4) = 5
(6X-X)/4 = 5
(5X)/4 = 5
5X = 20
X = 4
