Question

Quadrilateral ABCD is inscribed in a circle with angle measures m∠A = (11x − 8)°, m∠B = (3x2 + 1)°, m∠C = (15x + 32)°, and m∠D = (2x2 − 1)°. Are each of the following measures of the quadrilateral's angles? Select Yes or No for each statement.

m∠A = 135°
m∠B = 109°
m∠C = 227°
m∠D = 71°

Answer 1

No for all of the 4 values

Explanation:

The sum of the internal angles of a quadrilateral is always 360°, so we have that:

m∠A + m∠B + m∠C + m∠D = 360

11x - 8 + 3x2 + 1 + 15x + 32 + 2x2 - 1 = 360

5x2 + 26x - 320 = 0

Solving the quadratic function using Bhaskara's formula, we have:

Delta = 26^2 + 4*5*320 = 7076

sqrt(Delta) = 84.12

x1 = (-26 + 84.12)/10 = 5.81

x2 = (-26 - 84.12)/10 = -11.01 (this value will generate negative angles, so it is not valid).

Now, finding the angles, we have:

m∠A = 11*5.81 - 8 = 55.91°

m∠B = 3*(5.81)^2 + 1 = 102.27­°

m∠C = 15*5.81 + 32 = 119.15°

m∠D = 2*(5.81)^2 - 1 = 66.51°

As all these values are different from the values shown, the answer is No for all of them.