I feel like I should know this but I don’t please help

We must first determine the shape of a rectangular prisms _ a0 to find area of the prism

You and a friend race across a field to a fence and back. your friend has a 50-meter head start. the equations shown represent you and your friend's distances dd (in meters) from the fence tt seconds after the race begins. find the time at which you catch up to your friend. you: d=∣−5t+100∣d=∣−5t+100∣ your friend: d=∣−313t+50∣∣

Ineed me i stuck and i don’t want to get it wrong