Helps please
What is the answer for all of them?

Me find the missing dimension of a triangle height: 7 in., area: 21^2

Abe is a triangle. can you use the sss postulate or the sas postulate to prove triangle abc = triangle aed? by sss only neither apply both apply by sas only

Arley is building a model of a city map. in one part of the city, three roads form a right triangle, which harley draws as triangle abc, with the following measures: m∠b=90° and m∠a=30°. in his scale model, the hypotenuse of triangle abc, ac¯¯¯¯¯¯¯¯, has a length of 817−−√ cm. what is the value of a (the length of bc¯¯¯¯¯¯¯¯)?