Correct. The architect can use the Pythagorean Theorem, $\displaystyle{{c}}^{{2}}={{a}}^{{2}}+{{b}}^{{2}}\usepackage{cmbright}\Huge\$ , to find the length of the Bay Rd side if he knows the length of the park along Davis St, the length of the Foot Path, and the length of the Bike Path. He can find the length of Arlington St by using the lengths of Davis St and the Foot Path, and then he can find the length of Bay Rd by using Arlington St and the Bike Path.