they're the same triangle, but one is bigger. the 2,5 and 5 sides are equivalent, so with that we are able to know the big triangle is exactly 2x bigger. u multiply the 2 side (because it's equivalent to the x side) by 2 (bc the triangle is 2 times bigger) and you get 4 = x
ABCD is a diamond. Let's D' the intersection of the circle and DC. m∠BCD'=2*m∠BDC=2*45=90° m∠BCD=90° The diagonals of ABCD are perpendicular==>ABCD is a diamond and AB=BC=CD=DA=2
