In the Board of Aldermen chambers last night, Ken Matthews placed a classic right triangle onto an overhead projector — with sides of 3, 4 and x.

The instructions? “Find x.” The answer? Circling the letter “X,” according to Matthews, the New Haven Public Schools math supervisor.

After all, he said, answering “5” would have meant following a traditional educational mindset.

“We don’t teach mathematics like that anymore,” he said. “Especially in New Haven.”

Matthews was illustrating how New Haven Public Schools are experimenting with cutting-edge math education, such as the MATHCOUNTS program that sends Yale students to help mentor middle school students. That discussion was just one component in a nearly three-hour review of the city’s newest education initiatives.

During the meeting, which is held annually before the Board’s Education Committee, officials announced that the district will receive a three-year federal grant to convert three existing K-8 schools into inter-district magnet schools. The grant will also help cover the construction of a 6-12 school dedicated to science and math on or near the University of New Haven’s campus.

Ed Linehan, architect of the New Haven magnet school system, pointed out that the district has been more effective in attracting suburban students than in past years. At the same time, the magnet school program — already the largest in the state — is successfully expanding to more minority New Haven students than suburban minorities, according to statistics he displayed.

“We did have some real bright spots in some places, and we have some work to do in others,” superintendent Reginald Mayo said, adding that he will be putting a “really heavy emphasis” on writing next year.

Ward 9 Alderman Roland Lemar said he left the meeting excited but far from satisfied — a feeling he said is common when learning about public education in the city.

“You’re excited, yes … but you know that we’re not making the gains we should be making,” Lemar said. “You want it to be true, you realize the substantial gains they’ve made for the past 10 years under Reggie … but I want to start seeing double digit gains everywhere.”

Ward 25 Alderwoman Ina Silverman, who is the chairwoman of the Education Committee, said she was impressed by progress made over the past year.

“I’m thrilled it looks like the conversations we’ve had in the past years about developing curricula have come to fruition, and many of them are finished and in place,” she said. “And I’m very happy to hear about the increase in the scores.”

Following a five-year trend of rising test scores, the average SAT for New Haven students rose from 824 in 2006 to 828 this year on a 1600-point scale.

Although school construction has been the hot topic in the New Haven public school system in recent years, it constituted only one page in the information packet given to aldermen, underscoring district’s transition to a focus on the curriculum. Twenty-five New Haven schools have completed construction, five are currently under construction, and another five will begin construction or design soon.