39.Three concentric circles(同心圆)are shown.The two largest circles have radii of12and13.If thearea of the ring between the two largest circles equals the area of the smallest circle,determine the radiusof the smallest circle.((A)5(B)6(C)7(D)839.Three concentric circles(同心圆)are ...
Press and hold the down arrow key until you have only one circle. Tap the left arrow key until you have only three radii. Press and hold shift to constrain the circular proportion, then mouseup. But then I would be annoyed that the three pie slices have four points each. So...ho...
The inner radii of casing, cement and stratum are a, b, and c, respectively. It should be noted that in-situ compressive stresses in the stratum have been applied before well construction, so they represent the initial stress state for the casing-cement-stratum system. Then, the three ...