Answer:
The length of side KM is
units.
Explanation:
Given information: KLMN is a trapezoid, ∠N= ∠KML, FD=8, LM:KN=3:5, F∈ KL, D∈ MN , ME ⊥ KN KF=FL, MD=DN,
.
From the given information it is noticed that the point F and D are midpoints of KL and MN respectively. The height of the trapezoid is
.
Midsegment is a line segment which connects the midpoints of not parallel sides. The length of midsegment of average of parallel lines.
Since LM:KN=3:5, therefore LM is 3x and KN is 5x.
![(3x+5x)/(2)=8](https://img.qammunity.org/2019/formulas/mathematics/middle-school/syss1z8o4bgleuf4jey0zkhvy7y009v6rj.png)
![(8x)/(2)=8](https://img.qammunity.org/2019/formulas/mathematics/middle-school/c2tledzpxs05akhsak1qsf2slr0ga3lqsw.png)
![x=2](https://img.qammunity.org/2019/formulas/mathematics/college/j2ylgqzlqmqlm551uh73cj4i3ylurdli25.png)
Therefore the length of LM is 6 and length of KN is 10.
Draw perpendicular on KN form L and M.
![KN=KA+AE+EN](https://img.qammunity.org/2019/formulas/mathematics/middle-school/cx5g9jez08119u2sprj1rsdj5mqeacuw4k.png)
(KA=EN, isosceles trapezoid)
![EN=2](https://img.qammunity.org/2019/formulas/mathematics/middle-school/6nxpnw8vop8bcr9cyzu8nghax8kq6jyqqm.png)
![KE=KN-EN=10-2=8](https://img.qammunity.org/2019/formulas/mathematics/middle-school/xztdyk2rpd27loxurtsebie4o4redranvl.png)
Therefore the length of KE is 8.
Use pythagoras theorem is triangle EKM.
![Hypotenuse^2=base^2+perpendicular^2](https://img.qammunity.org/2019/formulas/mathematics/middle-school/xahoxn40kij80st2y2c1jtxfopfdky4h92.png)
![(KM)^2=(KE)^2+(ME)^2](https://img.qammunity.org/2019/formulas/mathematics/middle-school/vjizl2n5dkg4ze98242tt414lsbgk9xdkw.png)
![(KM)^2=(8)^2+(3√(5))^2](https://img.qammunity.org/2019/formulas/mathematics/middle-school/khived993tnzf74c0rujb766jrqy4j4pi7.png)
![KM^2=64+9(5)](https://img.qammunity.org/2019/formulas/mathematics/middle-school/2yajzgxougbnlp8ej9if2ea7kepadbd9kk.png)
![KM=√(109)](https://img.qammunity.org/2019/formulas/mathematics/middle-school/7x0cx3z4lurehugsyd4ctpkvkqlew1b6dp.png)
Therefore the length of side KM is
units.