The mystery of the shapes
The Sun Festival was next week. Tira and Walum hurried to Glad Hand’s store to buy a festival present for Deely, their favourite cousin. The only way to the store was through a narrow lane that was sometimes blocked by the bratty Bilow kids. Tira crossed her toes, hoping that today was not one of those days. The way looked clear. But about half down the lane two gates suddenly popped up, one behind and one ahead of Tira and Walum. They were trapped. Giggles sounded from both sides of the lane. Then a paper airplane with a note attached landed in Tira’s hands. She read the note.
Solve the mystery of the shapes to open the gates.
Each row and each column in the 3 x 3 grid adds up to 19.
The diagonals do not have to add up to 19.
The triangle shape is worth 7 and the square shape is worth 11.
How much are the other three shapes worth?

Tira and Walum began to think hard. The store was closing in 20 minutes.