This means that Eratosthenes estimated the circumference of the Earth to be about 40,000 km. He also knew that the circumference of a circle was equal to 2 times Ï (3.1415...) times the radius of the circle. (C = 2Ïr) With this information, Eratosthenes inferred that the Earth's radius was 6366 km.
Ankylosing spondylitis is a form of chronic inflammation of the spine and the sacroiliac joints. The sacroiliac joints are located at the base of the low back where the sacrum (the bone directly above the tailbone) meets the iliac bones (bones on either side of the upper buttocks) of the pelvis.
A. A. A. Ankylosing spondylitis is a type of arthritis that affects the spine. Ankylosing spondylitis symptoms include pain and stiffness from the neck down to the lower back.The spine 's bones (vertebrae) may grow or fuse together, resulting in a rigid spine.. A. A. Ankylosing spondylitis is a type of arthritis that affects the spine. Ankylosing spondylitis symptoms include pain and stiffness from the neck down to the lower back.