Inches per hour and centimeters per day I believe
Answer:
See explanation
Step-by-step explanation:
Given 
According to the order of the vertices,
- side AB in triangle ABC (the first and the second vertices) is congruent to side AD in triangle ADC (the first and the second vertices);
- side BC in triangle ABC (the second and the third vertices) is congruent to side DC in triangle ADC (the second and the third vertices);
- side AC in triangle ABC (the first and the third vertices) is congruent to side AC in triangle ADC (the first and the third vertices);
- angle BAC in triangle ABC is congruent to angle DAC in triangle ADC (the first vertex in each triangle is in the middle when naming the angles);
- angle ABC in triangle ABC is congruent to angle ADC in triangle ADC (the second vertex in each triangle is in the middle when naming the angles);
- angle BCA in triangle ABC is congruent to angle DCA in triangle ADC (the third vertex in each triangle is in the middle when naming the angles);
Answer:
Perimeter is 17.07
Step-by-step explanation:
We know that DF = EF = 5 cm, since D and E are the midpoints of AC and AB, both of which are 10 cm in length.
We need to use the Pythagorean theorem to get the length of DE.

So the perimeter of DEF is 5 + 5 + 7.07 = 17.07
Answer:
√841
Step-by-step explanation:
You would use pythagorean theorem to solve this problem:
a² + b² = c²
a = 20 b = 21
20² + 21² = 400 + 441 = 841
√841