Go to the Add Objects palette, click on the AutoShapes icon and choose the triangle. Draw the triangle, select and right click on the triangle and Add Text.
Go to the Add Objects palette, click on the AutoShapes icon and choose the triangle. Draw the triangle, select and right click on the triangle and Add Text.
It can't be done in Word, as the OP himself has said. Adding text to a triangle formats it in a rectangular box. But if the OP really, really needs to do this, he could invest $90 in iWork or download the 30 day trial from http://www.apple.com/iwork/trial/