Perpendicular means like making 4 right angles at the intersection, right? So do a light directly upwards through line t from point a. And for 2, do a line from point a to the center of BC, B to the center of AC, and C to the center of AB
1. we know she needs 3 packs of biscuits 2. Shop A you only need to pay for 2 packs 3. Shop B you only need to pay for 2 packs 4. Shop C you need to pay for all three 5. so we know C is out of the option.