YARN Cotton yarn
HOOK 4.5 MM
Sc: single crochet
sl st: slip stitch
ch2, sc in the 2nd ch from the hook, turn.
Row 1 :Ch1, 2sc in the st.
Row 2 :Ch1,sc in the first st, 2sc in the next st.
Row 3 :Ch1, sc in the 1st st, sc in the next st, 2 sc in the last st.
Row4: Ch1, sc in the 1st st, sc in the next 2 st, 2sc in the last st
Row5: ch1, sc in the 1st , sc in every st, 2 sc in the last st.
Repeat row 5 till you obtain the width you want.
For my triangle I did 20 rows.