Triangle D E F is shown. The length of E F is 10, the length of D F is 7, and the length of D E is 12. What information relevant to calculating area do we have available for this triangle? Which method should we use to calculate the area for this triangle? What is the area of this triangle calculated to the nearest hundredth of a square unit?

34.98 square units.

Step-by-step explanation:

It is given that DEF is a triangle, EF=10, DF=7 and DE=12.

Information of sides of triangle is relevant to calculating area.

We should use Heron's formula.

According to Heron's formula, the area of triangle is

where,  

For triangle DEF, let a=10, b=7 and c=12.

Now,

Area of triangle is

Therefore, the area of triangle DEF is 34.98 square units.

answer set (b) 0.5, 3/4 80% is in order from least to greatest.  

step-by-step explanation:

in order to compare rational numbers to each other, it is much easier if they are in the same form.   typically, the best form in which to evaluate rational numbers is in decimals.   in order to convert a percent to a decimal, you would divide the given percentage by 100.   you can also accomplish the conversion by moving the decimal point over two places to the left.   for example, the decimal value of 80% is 80/100, or 0.8.   in order to convert a fraction to a decimal, you need to divide the numerator by the denominator.   for example, 3/4 is 0.75.   so, for choice (b) 0.5 3/4 (0.75), 80% (0.8) is the only choice in which the numbers are in order from least to greatest.