Question

Isosceles Triangle Problem

Answer 1

@Loser66

Answer 2

\(\Delta BDE\) and \(\Delta CDF\) are similar. You know this because angles \(\angle ABC\) and \(\angle ACB\) are congruent, and they are both right triangles, so the remaining angles \(\angle BDE\) and \(\angle CDF\) must also be congruent.

Answer 3

Did I mention I can't use a calculator at all?

Answer 4

so what do I do now?

Answer 5

i don't think we need a calculator for this question hmmmm
according to what he/she said:
we can set up a proportion:
i was looking at this link ( http://www.mathplanet.com/education/geometry/similarity/triangles ) : if the triangles are similar then their corresponding sides are proportional

Answer 6

we can separate both right triangles
\[\huge\rm \frac{ BD }{ CD } = \frac{ DE }{ DF}\]
given `DE : DF ` 5:7 and bec BD/CD is equal to DE/DF
we can say the ratio of `BD :CD` is also 5:7