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.

The sum of the interior angles of a triangle is 180°:
180° = a° + b° + c°
c° = 180° - a° - b°
c° = 180° - 39° - 46° = 95°

To combine like terms, add or subtract the coefficients (the numbers that come before the variables) of terms that have the same variable raised to the same exponent.

8a - 7a = 1a

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

You need to find the value of b so solve the first equation in terms of y:

7b + y = 3
y = 3 - 7b

then substitute the result (3 - 7b) into the second equation:

-3b + 3(3 - 7b) = -7
-3b + (3 x 3) + (3 x -7b) = -7
-3b + 9 - 21b = -7
-3b - 21b = -7 - 9
-24b = -16
b = \( \frac{-16}{-24} \)
b = \(\frac{2}{3}\)