#### Transcript of Da Vinci's Proof

Beginning of Proof

Prove that O is the center of the square ACJI, so that line BH goes through it.

Given: Triangle ABC is a right triangle, line HI is congruent to BC, HJ is congruent to BA, and O is the midpoint of line HB

1st.) Expand line BC and HJ until they meet at point K.

2ND.) Expand line BA and IH until they meet at point L.This makes square BKHL, now draw line IC.

3rd.) Prove triangles IOH and COB are congruent with ASA. A:Angles IBH and COB are congruent by vertical angles. S: Line BO is equal to HO because O is the midpoint of BH. A:Angles OBC and OHI are equal by alternate interior angles with lines BK and LH. SO line IO is equal to OC and O is the center of square ACJI.

Finding the Quadrilaterals

We have to prove next that angle DBG is a straight angle. We know that the diagonals of a square are angle bisectors, so angle DBE(45)+ angle EBF(90)+ angle FBG(45)=180

Continuing Proof

Next we need to prove that the quadrilaterals ABHI, JHBC,EDGF, and ADGC are all congruent to each other.

To prove the quadrilaterals, you require three angles and three sides. Sides HI = BC = CG = FG, AD = ED =AB = HJ, AI= CJ = EF = AC. Angles IHO = CBO = CGB = FGB, GFE = GCA = HIA = BCJ, FEB = CDA = CJH = IAB, ABH = JHB = ADG = EDG. We know this because of the sides of the squares and the congruent triangles, which we'll prove next.

Leonardo Da Vinci

The Diagram

**Da Vinci's Proof**

Lived from 1452 to 1519

Born and lived in Florence, Italy

Best known as an artist (

The Last Supper, Mona Lisa

)

Also made many scientific progress

Appeared in Assassin Creed

Leonardo Davinci

Assassin's Creed Davinci

Continuing Proof Again

Triangle JHI = Triangle ABC by SSS, S:HJ = AB, S:BC = HI, S:AC = JI. Then we know that Triangle ABC is congruent to Triangle EBF by SAS, S:AB = EB, A:ABC = EBF, S:BC = BF

The Key Idea

Because of the knowledge of the quadrilaterals being congruent then the hexagons are congruent. One hexagon has Squares A and B and two congruent triangles. The next hexagon has Square C and two congruent triangles. So the sum of the Squares A and B is equal to Square C, proving the Pythagorean Theorem.

Full transcript