What is the measure of ac ? enter your answer in the box. ° circle with inscribed angle a b c. angle a b c is 3 x minus 1.5 degrees. the intercepted arc a c is 3 x plus 9 degrees.

Inscribed angles are 1/2 of the measure of the intercepted arc.  That means from this we have the equation
.  Distribute the 1/2:

We cannot have a variable on both sides of the equation, so cancel the 1.5x to avoid negatives:

Combine like terms:

Cancel the -1.5 by adding:

Divide both sides by 1.5:

Since AC is 3x+9, we substitute 4 in for x:
3*4+9=12+9=21°

Answer: d. 39 cmin the diagram, the approximate length of the minor arc de is 39 centimetres.step-by-step explanation: the formula for the length of an arc in a circle is as displayed below.let the length of the minor arc de = xx = 2( pi )r × angle of sector / 360°from this, we will substitute the values given from the problem into the formula to obtain the length of the minor arc de.x = 2( pi )r × angle of sector / 360°r = radius = 25cmpi as an approximate value = 3.14angle of sector = 120°x = 2( 3.14 )( 25 ) × 120° / 360°x = 157 × 1 / 4x = 39.25x = 39 ( rounded to the nearest whole number as an approximate value )