## InsanityxP Group Title What is the surface area of the composite figure? ~Attachment in comments~ 2 years ago 2 years ago

1. InsanityxP Group Title

2. Shane_B Group Title

Take it in pieces and sum up the values at the end. It's going to be:$SA_{bottom}+4SA_{side}+4SA_{triangle~side}$

3. Shane_B Group Title

If you're stumped on this let me know and I'll walk you through it.

4. InsanityxP Group Title

It would help if you could walk me through it, please?

5. Shane_B Group Title

Ok, the bottom of the figure is a square with 6mm sides right? Well, the SA of a square is just side*side: $6mm*6mm=36mm^2$

6. Shane_B Group Title

The sides are rectangles so it's basically SA = LW:$7mm*6mm=42mm^2$

7. Shane_B Group Title

The top parts are just triangles with a 6mm base and a height of 4mm. The SA of a triangle is (1/2)bh:$\frac{(6mm)(4mm)}{2}=12mm^2$

8. Shane_B Group Title

Now use the first equation I posted which sums it all up to get the total surface area. If you work it out I'll double-check your answer.

9. InsanityxP Group Title

For some reason I've got 90 mm^2 but that's not even close to one of the answers I have :/

10. Shane_B Group Title

I think I lost you...here:$SA_{total}=SA_{bottom}+4SA_{side}+4SA_{triangle~side}$$SA_{total}=36+4(42)+4(12)=?$

11. Shane_B Group Title

There's no magic formula when doing these types of problems. You just take the individual areas and sum them up at the end.

12. InsanityxP Group Title

252 mm^2?

13. Shane_B Group Title

Yes

14. InsanityxP Group Title

Thank you!

15. Shane_B Group Title

yw, good luck :)