Answer:
concave polygones
Step-by-step explanation:

Regardless of the sign of

, we have

(never negative). But multiplying by -1 makes it negative.
On the other hand,

which can never be negative for real

.
First, you add up the total number of students because we would base our percentage one this.
Total number of students = 1+4+5+10+20+10+5
Total number of students = 55
Now, let's count how many of them got a score of more than 70. For this, you would only count the students belonging to 70-under 80, 80-under 90 and 90-under 100.
Students who got more than 70 = 20+ 10 + 5 = 35
Therefore the percentage is equal to:
Percentage = 35/55 * 100 = 63.64%
Answer:
Step-by-step explanation:
Answer:
<u>131 seats</u> are in the 30th row.
Step-by-step explanation:
The theater is designed with the first row there are 15 seats, in second row 19 seats and in the third row there are 23 seats.
Now, to find the number of seats in the 30th row.
So, we get the common difference(
) from the arithmetic sequence first:

Thus,
So, the first tem
= 15.
The number of last row (
) = 30.
Now, to get the number of seat in the 30th row we put formula:





Therefore, 131 seats are in the 30th row.