Somebody i need help please help me don't make useless

Triangle ABD is isosceles with AB = AD

=> angle ADB = angle ABD = 72 deg

The sum of 3 angles inside triangle ABD is equal to 180 deg

=> angle BAD + angle ADB + angle ABD = 180 deg

=> angle BAD = 180 - angle ADB - angle ABD = 180 - 72 -72 = 36 deg

Triangle ABC is isosceles with BA = BC

=> angle BCA = angle BAC = angle BAD = 36 deg

=> angle BCD = angle BCD = 36 deg (1)

The sum of 3 angles inside triangle ABC is equal to 180 deg

=> angle ABC + angle BCA + angle BAC = 180 deg

=> angle ABC = 180 - angle BCA - angle BAC = 180 - 36 - 36 = 108 deg

As shown in picture,

angle ABD + angle CBD = angle ABC

=> angle CBD = angle ABC - angle ABD = 108 - 72 = 36 deg (2)

From (1) and (2)

=> angle CBD = angle BCD = 36 deg

=> triangle CDB is isosceles with DC = DB

Hope this helps!

:)

the answer would be 150 books

step-by-step explanation:

if you divide 300 by 2 you will get 150