I am assuming you wrote the problem wrong. Is it a^2?
A^2 -4A-21=0
(A-7)(A+3)=0
A=7 A=-3, ignore the negative number because it doesn't make sense if you plug in for a.
length=a+3=7+3=10
Width=7=a
Answer:
The variance of the temperatures of the 10 day period must be at least zero.
Step-by-step explanation:
The variance is the expectation of the squared deviation of a random variable from its mean. It measures how far a set of numbers are spread out from their average value.
Its unit of measure corresponding to the square of the unit of measure of the variable. In this case, the variance of the temperatures is expressed in (°C)². The variance has a minimum value of 0.
Since the variance is squared, it will always have values greater than zero.
To find the lateral area you will find the area of all 4 faces that are perpendicular to the base.
You will multiply the side by the length (front/back) and the side by the width (sides).
12 x 8 = 96
12 x 2 = 24
120 square inches x 2 = 240 square inches
The lateral area is 240 square inches.
The area of the base is 8 x 2 = 16 square inches.
16 x 2 = 32 square inches
240 square inches + 32 square inches = 272 square inches is the surface area.
Congruent to angle 1: 3, 5, 10, 8, and 6
congruent to angle 2: 4, 9, and 7
