Help me Find the axis of symmetry

1. during first 10 seconds 2. between 10 seconds and 35 seconds 3. during 35 seconds to 40 seconds

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¯¯¯¯¯¯¯¯)?

Lucy and donavan measured the length of the school garden. lucys measurement is 11.3m and donavans measurement is 113 cm. could both be correct? explain