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.

Perimeter is equal to the sum of the four sides:

p = a + b + c + d
p = 9 + 2 + 5 + 7
p = 23

The first step to solve a quadratic expression that's not set to zero is to solve the equation so that it is set to zero:

x² - 6x + 26 = 5x - 2
x² - 6x + 26 + 2 = 5x
x² - 6x - 5x + 28 = 0
x² - 11x + 28 = 0

Next, factor the quadratic equation:

x² - 11x + 28 = 0
(x - 4)(x - 7) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (x - 4) or (x - 7) must equal zero:

If (x - 4) = 0, x must equal 4
If (x - 7) = 0, x must equal 7

So the solution is that x = 4 or 7

To solve this equation, isolate the variable for which you are solving (b) on one side of the equation and put everything else on the other side.

5b + 3z = -2b + 3z - 3
5b = -2b + 3z - 3 - 3z
5b + 2b = 3z - 3 - 3z
7b = - 3
b = \( \frac{ - 3}{7} \)
b = \( \frac{}{7} \) + \( \frac{-3}{7} \)
b = z - \(\frac{3}{7}\)

The sum of the interior angles of a triangle is 180°:
180° = a° + b° + c°
c° = 180° - a° - b°
c° = 180° - 49° - 56° = 75°