i have a question with the answer that i have to explain why that is the correct answer please explain to me why that answer is right .5. What is the probability that a point randomly chosen in the large triangle is also in Region A? answer is 75%

Question

i have a question with the answer that i have to explain why that is the correct answer please explain to me why that answer is right .5.	What is the probability that a point randomly chosen in the large triangle is also in Region A? answer is 75%

anonymous · Answer

here is the graph

anonymous · Answer

this is Geometric Probability

jim_thompson5910 · Answer

what is the area of the larger triangle?

anonymous · Answer

it just shows the picture of the graph and some numbers on there 
it just saids the answer is 75% and to explain why is that

jim_thompson5910 · Answer

are you able to find the area of the larger triangle?

anonymous · Answer

no can you help me please

jim_thompson5910 · Answer

we have this triangle, agreed?
|dw:1427332600001:dw|

anonymous · Answer

yes

jim_thompson5910 · Answer

the area of this triangle is 

A = (b*h)/2 = (14*10)/2 = 140/2 = 70

jim_thompson5910 · Answer

The smaller triangle looks like this

|dw:1427332968953:dw|

jim_thompson5910 · Answer

what is the area of this triangle?

anonymous · Answer

17.5?

jim_thompson5910 · Answer

yes

jim_thompson5910 · Answer

so we divide the smaller triangle area by the larger triangle area

17.5/70 = 0.25

therefore, 25% of the area is just in the smaller triangle (and not in region A)

jim_thompson5910 · Answer

so 100% - 25% = 75% must be in the remaining bit of area, aka region A

anonymous · Answer

oh okay i think i get it so first we had to find the areas for both triangles then divide the answers and got 25% take that away from a 100 and thats how we get 75%