Evaluate the expression for the given value of the variables. 0.7d - 2.31
d = 13, f = 3
0.7d - 2.3f=
= (Type an integer or a decimal.)

In trapezoid efgh, m∠hef=(4x2+16)∘ and m∠gfe=(5x2+12)∘. find the value of x so that efgh is isosceles.

What is the ratio for the surface areas of the cones shown below, given that they are similar and that the ratio of their radil and altitudes is 4: 3? 23

Anyone? 15m is what percent of 60m; 3m; 30m; 1.5 km?