Help Please 100 pts for the answer! Need answer ASAP

(urgent ) use pi 3.14 to estimate the circumference of the circle to the nearest hundredth middle is 4in (urgent )

Can someone me with my math problems i have a bunch. i will give brainliest and lots of pleeeaaasssee

With these 5 geometry questions! pls 1.)quadrilateral abcd is inscribed in this circle.what is the measure of ∠a ? enter your answer in the box.°2.)quadrilateral abcd is inscribed in a circle.what is the measure of angle a? enter your answer in the box.m∠a= 3.)quadrilateral abcd is inscribed in this circle.what is the measure of angle b? enter your answer in the box.m∠b= °4.)quadrilateral abcd is inscribed in this circle.what is the measure of angle a? enter your answer in the box.°5.) quadrilateral abcd is inscribed in this circle.what is the measure of angle c? enter your answer in the box.°