The formula for area is πr². Radius is circle \( \frac{diameter}{2} \):

r = \( \frac{d}{2} \)
r = \( \frac{10}{2} \)
r = 5
a = πr²
a = π(5²)
a = 25π

The first step to solve a quadratic equation that's set to zero is to factor the quadratic equation:

b² - 4b + 3 = 0
(b - 1)(b - 3) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (b - 1) or (b - 3) must equal zero:

If (b - 1) = 0, b must equal 1
If (b - 3) = 0, b must equal 3

So the solution is that b = 1 or 3

To multiply monomials, multiply the coefficients (the numbers that come before the variables) of each term, add the exponents of like variables, and multiply the different variables together.

(2a)(4ab) + (9a²)(6b)
(2 x 4)(a x a x b) + (9 x 6)(a² x b)
(8)(a¹⁺¹ x b) + (54)(a²b)
8a²b + 54a²b
62a²b

To factor a quadratic expression, apply the FOIL method (First, Outside, Inside, Last) in reverse. First, find the two Last terms that will multiply to produce 9 as well and sum (Inside, Outside) to equal 6. For this problem, those two numbers are 3 and 3. Then, plug these into a set of binomials using the square root of the First variable (y²):

y² + 6y + 9
y² + (3 + 3)y + (3 x 3)
(y + 3)(y + 3)

The circumference of a circle is the distance around its perimeter and equals π (approx. 3.14159) x diameter: c = π d. The area of a circle is π x (radius)² : a = π r².