Someone please help me with areas of shapes on a grid, I really need to be able to graduate, all the rest of my grades in other subjects are great.

Question

sbuck98 · Answer

@jim_thompson5910

jim_thompson5910 · Answer

see attached for a hint

jim_thompson5910 · Answer

let me know if that helps or not

sbuck98 · Answer

20?

sbuck98 · Answer

@jim_thompson5910

jim_thompson5910 · Answer

The area of the overall red rectangle (biggest red rectangle that surrounds the whole triangle) is 20

but you want the area of the triangle in light blue

sbuck98 · Answer

I'm not sure how to do that at alll, could you please help?

jim_thompson5910 · Answer

step 1) find the area of the biggest red rectangle, that would be 20 square units

step 2) subtract off the areas of region A, region B, region C, region D. See attached

sbuck98 · Answer

4

jim_thompson5910 · Answer

what's the area of region A?

sbuck98 · Answer

9

jim_thompson5910 · Answer

how are you getting 9?

sbuck98 · Answer

9 full blocks

jim_thompson5910 · Answer

do you see how region A is a triangle?

use the area of a triangle formula

sbuck98 · Answer

I don't know any of this, at all

jim_thompson5910 · Answer

area of triangle = base*height/2

sbuck98 · Answer

4*4/2=8

jim_thompson5910 · Answer

the base is 5, not 4

sbuck98 · Answer

5*4/2 10

jchick · Answer

Do you know the distance formula?

jim_thompson5910 · Answer

area of region A = 10 square units
correct

jim_thompson5910 · Answer

do the same for region B and tell me what you get

sbuck98 · Answer

3*1/2=1.5

jchick · Answer

@jim_thompson5910 the distance formula is a very standard way to solve this. Simply put numbers on the graph and it will be more accurate and quicker/easier.

jim_thompson5910 · Answer

@sbuck98 you made an error, try again

you're miscounting the units along the base for region B

sbuck98 · Answer

I don't get this:(((((((

jim_thompson5910 · Answer

@jchick yes you could find the lengths of the sides then use Heron's formula but that takes much longer

jim_thompson5910 · Answer

region B has a base of 4. Do you see why?

jim_thompson5910 · Answer

start at the corner and count 4 units til you get to the tip of the triangle

jchick · Answer

Correct @jim_thompson5910 but as you probably will agree that the more time you spend the more likely it is to be correct.

sbuck98 · Answer

@jim_thompson5910  why'd you just leave?