△ CDB and△ ACD are right triangles.
∴CD? =BC? -DB? =AC? -Advertising? (Pythagorean theorem)
And ∵AD=AB-DB AB=5, BC=4, AC=6.
∴4? -DB? =6? -(AB-DB)?
4? -DB? =6? -(5 decibels)?
16-DB? =36-(5? - 10DB+DB? )
16-DB? =36-25+ 10DB-DB?
16-DB? = 1 1+ 10DB-DB?
Add DB on both sides?
16 = 1 1+ 10DB
5= 10DB
DB= 1/2=0.5
∫CE is the center line of AB side.
∴E is the midpoint of AB
∴AE=EB
AB = 5
∴AB=2AE=2EB
∴5=2AE=2EB
AE=EB=5/2
∫EB = 5/2 DB = 1/2 = 0.5。
∴EB-DB=DE
∴DE=5/2- 1/2=4/2=2
②∵DE⊥AB in E,DF⊥AC in F.
BD? +CD?
= (Yes? +DE? )+(DF? +CF? )
∫∠BAC = 90 DE ⊥ AB in E,DF⊥AC in F.
∴ af ‖ deaedfadf is a parallelogram.
∵∠ BAC = 90 AEDF is a rectangle.
De? +DF? =EF? =AD? (Diagonal lines of rectangles are equal)
AB = AC,∠BAC=90
∴∠B=∠C=45
∵DE⊥AB is in E,DF⊥AC is in F.
∴∠EDB=∠FDC=45
∴△EBD,△FCD is an isosceles right triangle
∴BE=ED DF=CF
∵EB? +CF? =DE? +DF? =EF? =AD?
=2DE? +2DF?
=2AD?
③BC⊥AD
△ ACD and△ ACD are right triangles.
Ba? -DB? =AC? -CD? =AD?
∫BC = 14,AC= 15,AB= 13
Ba? -BD? =AC? -CD?
∴ 13? -BD? = 15? -CD?
∫BC = BD+CD
BD=BC-CD
BD= 14-CD
∴ 13? -( 14-CD)? = 15? -CD?
CD=9
△ ACD is a right triangle AC? -CD? =AD?
15? -9? =AD?
AD= 12 or AD=- 12 (omitted)
Give it to me, thank you!