How to do proportions - Telegraph How do you achieve the ideal ratios when you put an outfit together? There is more than one answer, and you don't need a maths degree to work it out. Mathematicians frequently debate the golden ratio. Designers do, too - but is there an equation for the most visually pleasing proportions in fashion? Well, that depends on when you're asking the question. A couple of years ago, the hit formula was high hemlines, higher heels and a tight, tight dress (designers called it body-con; Wags eventually redubbed it their uniform). Before that, it was all about Phoebe Philo at Chloé-era's school of oversized - a baggy smock with a clunky wedge. For a while, Balmain's shoulder-padded, skinny-jeans isosceles looked like the solution. Pose that question this spring, and you'll get a different answer - or answers, actually. The rules for proportions now: volume on top works with a slim bottom; flip the scenario, and you have an equally great pairing in the generous lower-half and tidy upper; a slender silhouette draws in the eye when anchored by big shoes. It's that play on supersized and skinny that will make your look fresh, that will keep it current. "Fashion is architecture: it is a matter of proportions," as Coco Chanel said (she really did have a natty quote for everything). Here are your building blocks for the season. VOLUMINOUS TOP + SLIM BOTTOM Cigarette-slim trousers and a capacious blouse are the bastions of this look. The best thing about big-up-top is that it gives the illusion of leaner legs. You're gunning for softly structured, rather than shapeless sack, though, so hunt out tops with gentle darting at the waist or bust to give the figure definition. And keep it simple: the volume is statement enough as it is. Instead, have fun with the bottoms with a print or embellishment. SLIM TOP + VOLUMINOUS BOTTOM Dior's fabulous full floral skirt worn with a tank is the dream here. There's something about the contrast between the opulent taffeta and low-key basic that just works. Maybe it's the clever way that casual tank instantly modernises what is essentially a very 1950s silhouette. If you're going down the trousers route, Céline's fluid draped ones paired with a form-fitting T-shirt cut one of the most elegant looks on the spring/summer catwalks. READ: Paris Fashion Week: Dior spring/summer 2013 SLIM SILHOUETTE + BIG SHOES Picture this Prada dress with kitten heels. It would still be lovely, but perhaps a bit too polite. And that's not Prada. What is Prada is that dress paired with a stonking pair of platforms. A shoe of substance adds edge by virtue of its clunkiness - Bottega Veneta's elegant LBD clashed with stompy loafers, and Erdem's delicate dresses and ramped-up T-bar courts. It's that frisson of the unexpected that you're aiming for. READ: Milan Fashion Week: Prada spring/summer 2013