The best method i found is guess-and-check. Just guess the three numbers. If you do this you should get 6+8+10.
Multiply 4.50 by 0.07
4.50*0.07 = 0.315
Then the sales tax is about $0.32.
You can also do it mentally. Moving the decimal point in 4.50 once to the left gives you 10% of the original amount, 0.45. Move it again to get 1% of the price, 0.045. Then multiply this by 7 to get 7%.
Answer:306
Step-by-step explanation:
since the width of the bottom square is 10, you split it between the triangles on top. You have to do this because 7 is not the whole width of the two triangles. So then the width of the triangles would be 12, 12 times 9 is 108, you'd have 216 total for both triangles and then the area of the square is 90, 90 plus 216 is 306.
