Given a circle with radius 4 cm, calculate (use π=3,14) the circumference, rounding off to two decimal places

Which angle has the same measure as the dehedral angle formed by the orange face and the purple rectangle

The volume of a spherical hot air balloon v(r) = 4 3 ? r3 changes as its radius changes. the radius is a function of time given by r(t) = 3t. find the instantaneous rate of change of the volume with respect to t at t = 2.

What is 140 squared pleas me i am dumb