#1

#4**0 **

My gut tells me that AD is 3*2 = 6...

So 2(3+3+4+5) = 2*15 = 30

Cphill probably meant AD is 2*4

hugomimihu
May 14, 2020

#3**+3 **

Yeah....that's a little confusing

Note that if angle B = angle D, than the tangents drawn from D have the same length as the tangents drawn from B

The tangents from B both have the length of 4 cm

So....the two tangents drawn from D have the same length

And the tangents drawn from A = 3cm

And the tangents drawn from C = 5cm

So

[ tangents drawn from B + tangents drawn from D + tangents drawn from A + tangents drawn from C] =

[ (4 + 4) + (4 + 4) + (3 + 3) +(5 + 5) ] =

[ 8 + 8 + 6 + 10] =

32 cm

CPhill May 14, 2020

#5**0 **

Also it appears that the radius(based on image) is 4.5 since 4 and 5 seem to be equally above/below it.

In that case the diameter is 9.

Hmm.

hugomimihu
May 14, 2020

#7**+3 **

Consider this, hugo

[ Remember that tangents drawn to a circle from an exterior point have equal lemgths ]

If we draw radii to the midpoints of AD . DC, AB,BC we will create congruent quadrilaterals

Therefore....the midpoint of BC to B = 4

And this is a tangent

And the midpoint of AB to B is a tangent with the same length

But since we have congruent quadrilaterals then the tangents drawn from D to the circle will have the same length as those drawn from B to the circle = 4

And the tangents drawn from A have the same length = 3

And the tangents drawn from C have the same length = 5

So...the perimeter is just 2 [ 4 + 4 + 5 + 3] = 32 cm

CPhill May 14, 2020