<prompt> A male 35 year old presents to the clinic with blackening and pain in upper anterior tooth. He also told that trauma to the tooth occurred 5 months ago. Intraoral findings reveal non-vital tooth 21. RCT was started and IOPA 21 taken for initial working length. After initial debridement of the canal was performed, another X-ray was captured with the initial root length measured and it appears that the file is approximately 4 mm from the apex. How could the doctor have obtained a more accurate initial length measurement?Increasing the vertical angulation of the cone in relation to the filmDecreasing the vertical angulation of the cone in relation to the filmDecreasing the horizontal angulation of the cone in relation to the filmIncreasing the horizontal angulation of the cone in relation to the film  <response>: In this case image foreshortening is there.Diagnostically unacceptable image distortion may require retaking the radiograph with a change in vertical angulation. The pattern of distortion should guide the radiographer to select an appropriate angle. Image foreshortening indicates that the vertical angulation is too high. In contrast, image elongation indicates insufficient vertical angulation. Changing the horizontal angulation of the cone in relation to the film will not change the length of the image. Reference: ORAL RADIOLOGY PRINCIPLES AND INTERPRETATION,8th EDITION, Stuart C. White,Michael J. Pharoah 