8×10= 80, so the rectangle is done. The formula for the area of a triangle is (l×w) /2 (we divide by 2 because a triangle with those dimensions has half the area of a square with the same dimensions). We know the length of the rectangle is 8, and the bottom length of the rectangle plus the length of the triangle is 14. Therefore, to know the length of the triangle, we must subtract 8 from 14. This gives us 6. The width of the rectangle is 10, but the length of the line above where the triangle ends is 5. 10-5= 5.
The equation is now:
(6×5) /2
According to PEMDAS, parenthesis are taken care of first. 6×5= 30. 30 /2 is 15. Remember to add the squared symbol to your answer because it's the square area!
Answer: 15 meters squared
---NO. 2---------------------------
This one is a little trickier. First, we have to separate the triangles from the rectangle. 15-8= 7, and 15/2= 7.5, so now that we have the lengths and widths for all the parts, we can treat the shapes separately. The rectangle is straightforward: 15×8= 120.
As for the triangles, this time we DON'T have to divide by 2. Since we have 2 identical triangles with the same area, the division of 2 and the multiplication of 2 since there are 2 triangles would cancel each other out. Also, 2 triangles makes a square, so we can just use that formula. 7.5×7= 52.5.
52.5+120= 172.5.
Answer: 172.5 meters squared
---NO. 3---------------------------
First, let's tackle that tiny rectangle in the top left. 7×3= 21. Now, the other rectangle with a length of 5 cm. We know from the first square that it all have a width of 3. 5×3= 15. And the largest rectangle is the simplest: 12×24= 288.
