Sam bought 4 new baseball trading cards to add to his collection. The next day his dog ate half of his collection. There are now only 30 cards left. How many cards did Sam start with?

geometry: triangles

solvers

lessons

answers archive

call the larger triangle abc

then the smaller triangle cde is similar to abc (all angles are equal, aaa).  

ab is the side that is 36, and we wish to find de, the side corresponding to ab

area_cde = area_abc - area_cde --> area_abc / area_cde = 2

let x=length of de

ratio of areas = (ratio of sides)^2

+2+=+%2836%2fx%29%5e2+

+2+=+1296%2fx%5e2+

++x%5e2+=+1296%2f2+=+648+

25.45584

answer: chelsea has 55 brushes

step-by-step explanation:

5 x 11 = 55

5 + 55 = 60

the transitive property of equality.

step-by-step explanation:

the correct answer is:

the transitive property of equality.

explanation:

we know that  ∠bcd is congruent to  ∠pbc. we also know that  ∠pbc is congruent to  ∠bad.

we can substitute  ∠bad for  ∠pbc in the first angle congruence statement to give us:

∠bcd is congruent to  ∠bad.

algebraically, the transitive property states if a=b and b=c, then a=c. it basically allows us to substitute equal values. since that is what we did, this is the transitive property.

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