Question: What kind of fellow has been, in turn, a rising tyro in modern dance; a star of American Ballet Theatre; the first American principal with the Royal Danish Ballet; and then artistic director of Ballet West, the fastest growing classical company on the yonder side of the Mississippi?

Answer: A burly Jewish kid from Brooklyn, with a truck driver for a father.

Bruce Marks, who meets all of the above requirements, installed Ballet West in the Kennedy Center Opera House last night, where it became the first American troupe not from the East Coast to play the hall.

A couple of weeks ago in Washington, dressed in a blue blazer and tie, he could have been your average gung-ho exec, but the pugilist shoulders, linebacker chest and lusty grin were giveaways to the strength and animal magnetism that have powered his bouncing-ball career.

"My dad was a weight lifter and tumbler," he said. "By the time I could walk I was a trained mini-acrobat." When a gym teacher at P.S. 244 suggested dance lessons, "I took the trolley to this studio on Flatbush Avenue above a store, and when they told me they offered free tap classes, I said, 'Okay, the price is right.' "

Shortly afterward, the new High School of Performing Arts opened and Marks auditioned. "After two months of lessons, there I was with my top hat, my cane, my tap shoes and my record of 'For Me and My Gal,' doing my walkovers and cartwheels. Another kid auditioning, jumping over our heads in the 'Bluebird' Variation, was a 13-year-old named Eddie Villella."

Villella made it, of course, and so did Marks, but immediately the faculty switched tracks on him. "They told me I was going to learn something called 'modern dance'; I had to buy some tights, and contort myself into weird positions. In two weeks, I was the world's most serious, dedicated, modern dancer." Martha Graham disciple Pearl Lang, on the school staff then, gave him the lead in a work called "Ironic Rite"--he was 14 at the time.

Marks danced for a number of years with Lang's troupe, creating a number of roles and partnering Lang herself. From Performing Arts he went on to Brandeis University and then to the Juilliard dance department, where the famed choreographer Antony Tudor took one look at him and announced, "You're going to be a ballet dancer!" Marks protested, citing his deep commitment to modern dance, but "you have no choice in the matter," said Tudor.

When Tudor thereafter began to choreograph for the Metropolitan Opera Ballet, he recruited Marks for the troupe. "The first time I had my name on a theater placard was in 'Lucia di Lammermoor'--it was Maria Callas' debut at the Met," Marks remembered.

Marks danced five years at the Met before joining ABT as a soloist in 1961. There he met his future wife, the outstanding Danish ballerina Toni Lander, then an ABT principal, and she gave him the leading male virtuoso role in "Etudes," which she staged for the company. After Marks mastered a slew of roles in record time, ABT director Lucia Chase told him she was promoting him to principal.

"I was scared stiff and didn't really want the title," Marks said. "Of course, the critics killed me--it took five years before I gained acceptance at ABT. When I did my first full-length role, Walter Terry, then dance critic at the Herald Tribune, showed me a piece he'd written in which he said I'd actually done it, made the transition from modern dancer to genuine ballet prince. The day the piece was to be published, the Trib went out of business."

Marks' perseverance paid off, though, and in time he became one of the most respected and versatile of ABT's male contingent; with his modern dance background, for example, he was the first to be cast in the title role of Jose Limon's "The Moor's Pavane" when ABT acquired this landmark opus. After his marriage to Lander in 1966, he also began to undertake guest engagements with such companies as the Royal Swedish Ballet, the London Festival Ballet and the Royal Danish Ballet. The Danish company, which had been seeking the return of Lander, engaged the couple in 1971, making Marks the first American in the troupe's uppermost ranks.

After five rewarding years abroad, Marks said, "I asked myself: you're rapidly approaching 40--what are you going to do with yourself in Denmark when you're not a Dane, and no longer dancing?" Then he remembered a letter he'd received some years earlier from Willam Christensen, the founder-director of Ballet West in Salt Lake City, asking if Marks would be interested in succeeding Christensen when the latter, then near 70, retired.

Once again Marks shifted occupational gears. In 1976, he became codirector of Ballet West with Christensen, and in 1978, upon the latter's retirement, artistic director of the Utah troupe. His wife Toni (they've since divorced but remain on "extremely amicable" terms) was named principal teacher of the company. She also has staged a number of works from the Danish repertory, including the "Etudes" seen last night at the Kennedy Center.

One of the major thrusts of Marks' directorship has been the encouragement of young choreographic talent. The ballet "Mistress of Sorrows" by Helen Douglas, also on last night's Ballet West repertory program, is among the fruits of this devotion. Douglas since has choreographed for ABT II, the Joffrey II Dancers and the Milwaukee Ballet, but at the time Marks first saw her work none of her choreography yet had been produced.

"I told her," Marks said, "we wanted to sign her to create three works over a three-year period. In astonishment, she asked why. I said, we want you to do work you really want to do; if we made it a one-shot, you'd be worrying constantly about 'success.' The important thing to us is that you be true to yourself."

This is typical of Marks' approach to gifted neophytes. "I believe," he'll tell you, "a young choreographer needs a serious opportunity to create, and assurance that his or her work will be produced. Too many companies throw on a new work, often in a workshop setting, as a kind of testing situation--if it proves out, then they'll produce, maybe. More than anyone, young choreographers need time to discover how to work; and if you have faith in their talent, you have to give them the chance, perhaps to fail, perhaps to succeed, but at least to learn from a long-term, professional experience."

Helen Douglas' first work for Ballet West under Marks' arrangement with her was "Esprit de Corps," to music by Schubert; her second, "Mistress of Sorrows," to a Howard Hanson score, is "loosely based on the Helen of Troy legend," Marks says. Douglas' third ballet for the company--to be premiered next year--will be a new setting of Stravinsky's "Rite of Spring." In the meantime, Ballet West has appointed her "resident choreographer," a further indication of Marks' confidence in her abilities.

Last night's program will be repeated Saturday afternoon and evening. Tonight (also tomorrow evening and Sunday matinee and evening), the troupe presents its unusual production of the full-length "Swan Lake."