Answer:
X= -7
Step-by-step explanation:
The rule for regular polygons are very easy. The number of reflectional symmetries is same as the number of sides. Regular polygons have all sides the same length and all angles same. Reflection symmetry means that you can fold the shape along that line and it will match up.
For this question, we want the number of reflectional symmetries of a regular decagon. Decagon is a 10 sided figure. Hence, the number of reflectional symmetries is 10.
There are 5 symmetry lines from one vertex to opposite vertex and 5 more symmetry lines form midpoint of one side to midpoint of opposite side.
ANSWER: 10
Now, let's do the same as we did for the previous one here.

notice again, how did we get 84 for the 4th element's coefficient? well 36 * 7 / 3. and so on. And you can just expand it from there.
Answer:
6.21 seconds
Step-by-step explanation:
The position function of a free-falling object is,

Where,
= initial height of the object,
= initial velocity of the object,
Here,


Hence, the height of the ball after t seconds,

When s(t) = 0,




∵ Time cannot be negative,
Hence, after 6.21 seconds the ball will reach the ground.
Answer:
205 years
Step-by-step explanation:
E=68 years
C=E+17=68+17=85 years
D=E-16=68-16=52 years
Total=E+C+D=68+85+52=205 years