Question

If m CDE=(3x+10)° m CDF=(x+25)°, and m EDF= 65°. Find m CDF​

Answer 1

m∠CDF + m∠EDF = ∠CDE

$x + 25° + 65° = 3x + 10$

$x + 90° = 3x + 10$

$90° = 3x + 10 - x$

$90° = 2x + 10$

$2x + 10 = 90$

$2x = 90 - 10$

$2x = 80$

$x = \frac{80}{2}$

$x = 40°$

m∠CDE

= 3 × 40 + 10

= 120 + 10

= 130°

Then , m∠CDF =

$x + 25 \\ = 40 + 25 \\ = 65°$

•°• m∠CDF = 65°