Question

Va rogggggg repede. Dau coroana​

Answer 1

∆ ABC isoscel AC=AB=6cm

<BAC =45⁰ ; BD _l_AC

a)Aria ∆BCD/aria∆ABD=?

∆ABD dreptunghic isoscel=>AD=BD

teorema lui Pitagora AB²=2AD²

AD=AB/√2=6/√2=3√2cm

DC=6-3√2=3(2-√2)cm

Aria ∆BCD=BD×DC/2=3(2-√2)×3√2/2=9√2-3cm²

aria∆ABD=AD×BD/2=3√2×3√2/2=9cm²

Aria ∆BCD/aria∆ABD=(9√2-3)/9=√2-1/3

b) distanța de la punctul D la AB este înălțimea

∆ADB dreptunghic isoacel =AB/2=6/2=3cm