Triangle DEF is congruent to TriangleD'EF' by the SSS theorem. Which single rigid transformation is required to map TriangleDEF onto TriangleD'EF'? dilation reflection rotation translation

B. reflection

Explanation:

Rigid transformations are methods involved in changing the dimensions or orientation of a given figure. The methods are; dilation, rotation, translation and reflection.

Reflection is the process in which a given figure is turned or flipped with respect to a point or line of reference.

In the given question,

ΔDEF ≅ ΔD'EF' (Side-Side-Side congruence property)

This implies that ΔDEF was reflected about point E to produce ΔD'EF'. Thus the required rigid transformation is reflection.

explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

            and  

since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.  

a is the correct answer