Elena wants to prove that a quadrilateral with 4 right angles must have congruent opposite sides. 1.)Explain to Elena how she can use the fact that all rectangles are parallelograms in her proof.

Please help!

i just took the test, the correct answer is .. 31.5 in.

the answer is: d) o, f, and kr.

atomic radius of bromine (br) is 114 pm.

atomic radius of oxygen (o) is 73 pm.

atomic radius of fluorine (f) is 72 pm.

atomic radius of krypron (kr) is 112 pm.

the atomic radius of a chemical element is a measure of the size of its atom.

the atomic radius varies with increasing atomic number, but usually increases because of increasing of number of electrons.

the atomic radius decreases across the periods because an increasing number of protons, because greater attraction between the protons and electrons.

could u provide us some answer choices or hmm idk maybe a table for us to anser with ? ?