Simplify 81 to the power of 3/4

What is the best approximation for the area of a circle with a radius of 4 m ? use 3.14 to approximate pi

Look at the figure below: triangle abc is a right triangle with angle abc equal to 90 degrees. the length of ac is 5 units and the length of ab is 4 units. d is a point above c. triangle adc is a right triangle with angle dac equal to 90 degrees and dc parallel to ab. what is the length, in units, of segment cd?

Hurry im being timed the graph of f(x)=x^3-3x^2+4 is shown based on the graph how many distinct real numbers solutions does the equation x^3-3x^2+4=0 have