Show that the area of a 13-14-15 triangle is 84. Compute mentally - 30 seconds tick tick tick...
I'm being silly with the ticking clock but it is possible to do this if you choose the "right" base! Unless of course you can mentally apply Heron's formula which is doable! Ok, so there's more than one way as always!
So what makes it special!? Somebody out there knows...
If you like these challenges consider purchasing my new Math Challenge Problem/Quiz Book - 175 questions - SAT format - with answers. Go to top of right sidebar to order.
Sent from my Verizon Wireless 4GLTE Phone
I'm being silly with the ticking clock but it is possible to do this if you choose the "right" base! Unless of course you can mentally apply Heron's formula which is doable! Ok, so there's more than one way as always!
So what makes it special!? Somebody out there knows...
If you like these challenges consider purchasing my new Math Challenge Problem/Quiz Book - 175 questions - SAT format - with answers. Go to top of right sidebar to order.
Sent from my Verizon Wireless 4GLTE Phone
Posts
2 comments:
If AB=15, AC=13, BC=14, altitude from A to BC is 10. Then the area is 84
Not too shabby for quick mental math but check your altitude. I believe the altitude on the "14" side is 12 not 10. If you're trying this with students, you may have to give them a hint if no one gets it after a min or two. Ask them if they recall any Pyth triples with either a 13 or 15 in them. It's still a little tricky but that should do it.
Post a Comment