△abc is similar to△qrs. also, side ab measures 50 cm, side ac measures 60 cm, and side qs measures 6 cm. what is the measure of side qr? show all your calculations!

The answer is that QR measures 5 cm.
As triangle ABC and QRS are similar ;
So, AC is similar to QS 
AC is 60cm and QS is 6 cm, it means if we divide the length of AC with 10 we get the measure of length QS
60/10 = 6 cm
S, AB is similar to QR and AB is 50cm, if we divide this with 10 we get the measure of QR
50/10 = 5 cm

4x 20 is 80 but if ther machine is broken then there is none you have to redo the test