A triangle has a base of units and a height of units. What is the area of the triangle, in square units?
For triangle area questions on the SAT, immediately write down the formula , substitute the given base and height, and do the arithmetic carefully—multiply base and height first, then divide by 2. Watch out for trap answers that come from just multiplying (forgetting the half) or from adding the two numbers instead of using the formula.
Hints
Identify the correct formula
What is the formula for the area of a triangle in terms of its base and height?
Use the given dimensions
Once you recall the formula, replace the base with 10 and the height with 7.
Do the operations in the right order
Be sure to multiply the base and height first, then apply the one-half factor. Do not add the base and height.
Desmos Guide
Compute the triangle area expression
In Desmos, type 0.5*10*7 (which represents ). The numeric result shown is the area of the triangle in square units.
Step-by-step Explanation
Recall the area formula for a triangle
The area of a triangle with base and height is given by
This means you multiply the base and height, then take half of that product.
Substitute the given base and height
You are told the base is 10 units and the height is 7 units, so plug these into the formula:
Multiply and then take half
First find the product . Then take half of 70:
So the area of the triangle is 35 square units, which corresponds to choice B.