👉 Learn how to solve problems with rectangles. A rectangle is a parallelogram with each of the angles a right angle. Some of ...

Take any quadrilateral such as ABCD above. Construct the midpoints of each side and join them to form another quadrilateral EFGH. Varignon's Theorem asserts that the ...

I HAVE read with much interest the new proof given by Mr. W. E. Johnson of “ the parallelogram of forces,” in NATURE of December 19 (p. 153), and regard it as deserving a place among the best proofs ...