The average is found by adding the numbers and dividing by 2.
Since the average is 17, the total of the two numbers must equal 17 x 2 = 34.
One number is given as 11, so subtract 11 from 34:
34 - 11 = 23
The other number is 23.
Too check: add 11 and 23 and then divide by 2:
11 + 23 = 34
34/2 = 17.
A regular trapezoid is shown in the picture attached.
We know that:
DC = minor base = 4
AB = major base = 7
AD = BC = lateral sides or legs = 5
Since the two legs have the same length, the trapezoid is isosceles and we can calculate AH by the formula:
AH = (AB - DC) ÷ 2
= (7 - 5) ÷ 2
= 2 ÷ 2
= 1
Now, we can apply the Pythagorean theorem in order to calculate DH:
DH = √(AD² - AH²)
= √(5² - 1²)
= √(25 - 1)
= √24
= 2√6
Last, we have all the information needed in order to calculate the area by the formula:

A = (7 + 5) × 2√6 ÷ 2
= 12√6
The area of the regular trapezoid is
12√6 square units.
If you treat multiplication as repeated a<span>ddition, then y</span>es, Juan is correct. Only equal groups can be multiplied.