Answer:
BC = 15
Step-by-step explanation:
Because of parallel lines, AD and BE, triangles ADC and BEC are similar.
In similar triangles, the lengths of corresponding sides are proportional.
AC/BC = DC/EC
We see that AC = AB + BC = 3 + BC
Also, DC = DE + EC = 2 + 10 = 12
(3 + BC)/BC = 12/10
(3 + BC)/BC = 6/5
Cross multiply.
5(3 + BC) = 6BC
15 + 5BC = 6BC
15 = BC
BC = 15
To find the answer,we can first calculate how much her sister took away by multiplying the original amount he has to the amount her sister took.
Her sister has:
7/12×2/5
=7/30
We can then find the amount of pizza left by deducting the pizza he has to the answer we found above:
7/12-7/30
=35/60- 14/60
=21/60
=7/20
Therefore he has 7/20 of a pizza left.
An alternative way to find the answer:
7/12×(1-2/5)
=7/12×3/5
=7/20
Hope it helps!
55%
Step-by-step explanation:
to findpercentages just divide 11/20. thenove the decimal place over 2 times
